Troubleshooting
Alarm and fault codes of common controllers
A selection of common alarm and fault codes, ordered by cause, with what they mean, what to check and which symptom to troubleshoot further.
Field mode: large buttons, questions first and the screen kept on.✓ Saved for offline use: troubleshooting works without coverage.Codes and meanings vary between controller models and firmware versions. Always check the manufacturer's manual for your unit. For guidance only; work on refrigeration and electrical systems must be carried out by qualified personnel. Terms of use
💡 Find a light signal (blinking or steady lamp)
All light signals of the chosen manufacturer (or of all) are shown below as lamps that blink as on the unit: faults and status lamps. Narrow them down with the colour and the number of flashes, and tap the one that matches to see what it means.
No exact match – these codes are close:
No code matches. The code may not be in the selection; read the manufacturer's manual.
Temperature too high
| Controller | Code |
|---|---|
| Danfoss ERC 21X[1] | A01 |
| Danfoss EKC 202A/B/C[2] | A1 |
| Danfoss AK-CC 550A[3] | A1 |
| Carel MPX[6] | HI |
| Carel MasterCella[7] | HI |
| Dixell XW270L/XW271L[9] | HA |
| Zanotti GM/GS[10] | AH1 |
| Carel ir33[11] | HI |
| Carel ir33[11] | HA |
| Carel ir33[11] | HF |
| Dixell XR60CX[12] | HA |
| Eliwell ID 974[13] | AH1 |
| Carel Heos[18] | HI |
| Carel ir33 universale[19] | E04 |
| Carel ir33 universale[19] | E15 |
| Carel ir33+ VCC[20] | HI |
| Carel ir33+ VCC[20] | HA |
| Carel MPXone[21] | HI |
| Carel MPXone[21] | HA |
| Carel SmartCella / SmartCella 3PH[24] | HI |
| Carel SmartCella / SmartCella 3PH[24] | HA |
| Carel SmartCella / SmartCella 3PH[24] | HF |
| Copeland EXD-SH1/2[26] | tAH1 |
| Heatcraft Beacon II[30] | A1 |
| Heatcraft Beacon II[30] | BOXHI |
| Danfoss AK-CC 450[32] | A1 |
| Danfoss AK-CC 450[32] | A13 |
| Danfoss AK-CC 450[32] | A70 |
| Danfoss AK-CC 450[32] | A72 |
| Danfoss AK-CC 550 / 550B[33] | A1 |
| Danfoss AK-CC 550 / 550B[33] | A13 |
| Danfoss AK-CC 550 / 550B[33] | A70 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | A01 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | A13 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | A70 |
| Danfoss AK-CC55 Water Loop[35] | A01 |
| Danfoss AK-CC 750[36] | High air temp. |
| Danfoss AK-CC 750[36] | High Prod. temp. |
| Danfoss Optyma control AK-RC 113[39] | EH |
| Danfoss EKC 202D1[41] | A1 |
| Danfoss EKC 202D1[41] | A8 |
| Danfoss EKE 1A/1B/1C/1D[43] | A993 |
| Danfoss EKE 100[44] | A28 |
| Danfoss AK-RC 251[47] | AH |
| Danfoss AK-RC 251[47] | HCP |
| Dixell XM669K/XM679K[50] | HA |
| Dixell XM669K/XM679K[50] | HA2 |
| Dixell XR06CX[51] | HA |
| Dixell XR35CX[52] | HA |
| Dixell XR460C[53] | HA |
| Dixell XR70CX[54] | HA |
| Dixell XW60K/XW60L[55] | HA |
| Dixell XWi70K[56] | HA |
| Carel µC2SE for process chiller[59] | Ht |
| Carel µChiller[60] | A15 |
| Secop SLV controller 105N46xx[81] | A20 |
| Secop SLV controller 105N46xx[81] | A60 |
| Secop SLV controller 105N46xx[81] | A75 |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | E20 |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | E21 |
| AHT GD-Cooler (GD-XLS, GD-XL)[84] | HA |
| AHT plug-in cases with Danfoss controller (Paris, Ibiza, Malta, Manhattan)[85] | Hi |
| Pego ECP200 EXPERT PULSE[89] | EH |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | EH |
| RDM DMTouch / miniDM[91] | Probe OT |
| RDM DMTouch / miniDM[91] | Pack CPT Fault |
| RDM Mercury 3 Twin Coil[92] | Ot AL |
| Störk-Tronic ST121 / ST501 / ST551[93] | Hi |
| Evco EV3203[107] | AH |
| Evco EV3 300 series[108] | AL |
| Evco EVK214[109] | AH |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | Ahi |
| Full Gauge TC-900E Log[118] | Athi |
| Full Gauge TC-940R[119] | AHi |
| Full Gauge MT-514E Faston[122] | Athi |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A05 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Ot |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Ot AL |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | LgOt |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | Ot |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | OT 1–OT 5 |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | Ot 1–Ot 6 |
| RDM Mercury AC and roof top unit controllers[130] | Evap. Out Temp. OT Alarm |
| RDM Mercury AC and roof top unit controllers[130] | Evap. In Temp. OT Alarm |
| RDM Mercury AC and roof top unit controllers[130] | Over Temperature |
| RDM Mercury AC and roof top unit controllers[130] | Ot AL |
| RDM ML Controller case controller[134] | AL |
| RDM ML Controller case controller[134] | PrAL |
| RDM DMTouch / miniDM[91] | CPT OT |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | Hi |
| Danfoss ETC (True cabinets)[142] | Hi |
| Danfoss EETa (True cabinets, LED blink codes)[143] | 1+1 flashes |
| Carel PQ (True cabinets)[144] | HI |
| Dixell XR/XW (True cabinets)[145] | HA |
| LAE AR2/BR1/BIT25 and BR+/CD25/TM (True cabinets)[146] | hi |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | AH1 |
| Taylor frozen beverage freezers C300, C302, C303/C314, 345/346/349/355[149] | BARREL TEMP 2 HIGH |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | HPR>41°F (5°C) AFTER 4 HR |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | BRL>41°F (5°C) AFTER 4 HR |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | HPR>45°F (7°C) AFTER 1 HR |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | HPR>59°F (15°C) |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | HPR>41F (5C) AFTER 4 HR |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | BRL>41F (5C) AFTER 4 HR |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | HPR>41F (5C) AFTER PF |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | BRL>41F (5C) AFTER PF |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | HPR>45F (7C) AFTER 1 HR |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | BRL>45F (7C) AFTER 1 HR |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | HPR>59F (15C) |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | BRL>59F (15C) |
| Taylor R160 frozen food dispenser[156] | HA |
| Dixell XR03CX/XR04CX (Hillphoenix display cases)[159] | HA |
| Carel MPXzero (Hillphoenix display cases)[160] | HI |
| Carel MPXzero (Hillphoenix display cases)[160] | HI2 |
| Carel MPXzero (Hillphoenix display cases)[160] | HA |
| Carel MPXzero (Hillphoenix display cases)[160] | HF |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | HI |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | HA |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | HF |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Case Temp Hi Limit Exceeded |
| LAE AT1-5/AT2-5[166] | HI |
| Pego 202BASE electronic board[167] | EH |
| BAC Nexus modular hybrid cooler (NXF controls)[172] | Al_LvgWaterTempHigh |
| BAC TrilliumSeries adiabatic cooler TRF[174] | 18 |
| LAE BR1-27/BR1-28/BR5-A/BR5-B/BD1-28/CD25[165] | HI |
| Carel MPXone[21] | HACCP LED flashingA HACCP alarm (HA/HF, temperature too high for too long) has occurred. (The manual does not give the colour.) HACCP symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | Icon HACCP onHACCP alarm (high temperature during operation or after power failure) is active. (The manual does not give the colour.) HACCP symbol: red steady |
| AHT electronic controller (plug-in cases, standard)[82] | Warning lamp 5 redOptional warning lamp: the cabinet is too warm (also lit after restart until the temperature is reached). Alarm symbol: red steady |
| AHT electronic controller (plug-in cases, standard)[82] | Display flashing temperatureElectronic controller: excessive temperature alarm. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-RC 251[47] | Icon HACCP steadyHACCP alarm active: room above h1 for longer than h2. (The manual does not give the colour.) HACCP symbol: red steady |
| Danfoss AK-RC 251[47] | Icon HACCP flashingA HACCP alarm has been recorded and not yet confirmed; press mute to confirm. (The manual does not give the colour.) HACCP symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel µChiller[60] | Cooling mode icon flashingWater temperature is too high. (The manual does not give the colour.) Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
The air temperature has been above the set high temperature limit for longer than the alarm delay.
Check: Check that compressor, fans and defrost work and that the door is closed. Compare the sensor with a calibrated thermometer.
Temperature too low
| Controller | Code |
|---|---|
| Danfoss ERC 21X[1] | A02 |
| Danfoss EKC 202A/B/C[2] | A2 |
| Danfoss AK-CC 550A[3] | A2 |
| Carel MPX[6] | LO |
| Carel MasterCella[7] | LO |
| Dixell XW270L/XW271L[9] | LA |
| Zanotti GM/GS[10] | AL1 |
| Carel ir33[11] | LO |
| Dixell XR60CX[12] | LA |
| Eliwell ID 974[13] | AL1 |
| Carel Heos[18] | Lo |
| Carel ir33 universale[19] | E05 |
| Carel ir33 universale[19] | E16 |
| Carel ir33+ VCC[20] | LO |
| Carel MPXone[21] | LO |
| Carel SmartCella / SmartCella 3PH[24] | LO |
| Copeland EXD-SH1/2[26] | tAL1 |
| Heatcraft Beacon II[30] | A2 |
| Heatcraft Beacon II[30] | BOXLO |
| Danfoss AK-CC 450[32] | A2 |
| Danfoss AK-CC 450[32] | A14 |
| Danfoss AK-CC 450[32] | A71 |
| Danfoss AK-CC 450[32] | A73 |
| Danfoss AK-CC 550 / 550B[33] | A2 |
| Danfoss AK-CC 550 / 550B[33] | A14 |
| Danfoss AK-CC 550 / 550B[33] | A71 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | A02 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | A14 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | A71 |
| Danfoss AK-CC55 Water Loop[35] | A02 |
| Danfoss AK-CC 750[36] | Low air temp. |
| Danfoss AK-CC 750[36] | Frost protection, too low S4 |
| Danfoss AK-CC 750[36] | Low prod. temp. |
| Danfoss Optyma control AK-RC 113[39] | EL |
| Danfoss EKC 202D1[41] | A2 |
| Danfoss EKC 202D1[41] | A9 |
| Danfoss EKE 1A/1B/1C/1D[43] | A992 |
| Danfoss EKE 100[44] | A29 |
| Danfoss AK-RC 251[47] | AL |
| Dixell XM669K/XM679K[50] | LA |
| Dixell XM669K/XM679K[50] | LA2 |
| Dixell XR06CX[51] | LA |
| Dixell XR35CX[52] | LA |
| Dixell XR460C[53] | LA |
| Dixell XR70CX[54] | LA |
| Dixell XW60K/XW60L[55] | LA |
| Dixell XWi70K[56] | LA |
| Carel µC2SE for process chiller[59] | Lt |
| Secop SLV controller 105N46xx[81] | A43 |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | E43 |
| AHT GD-Cooler (GD-XLS, GD-XL)[84] | LA |
| AHT plug-in cases with Danfoss controller (Paris, Ibiza, Malta, Manhattan)[85] | Lo |
| Pego ECP200 EXPERT PULSE[89] | EL |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | EL |
| RDM DMTouch / miniDM[91] | Probe UT |
| RDM Mercury 3 Twin Coil[92] | Ut AL |
| Störk-Tronic ST121 / ST501 / ST551[93] | Lo |
| Evco EV3203[107] | AL |
| Evco EVK214[109] | AL |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | Alo |
| Full Gauge TC-900E Log[118] | Atlo |
| Full Gauge TC-940R[119] | ALo |
| Full Gauge MT-514E Faston[122] | Atlo |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A02 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Ut |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Ut AL |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | LgUt |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | Ut |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | UT 1–UT 5 |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | Ut 1–Ut 6 |
| RDM Mercury AC and roof top unit controllers[130] | Evap. Out Temp. UT Alarm |
| RDM Mercury AC and roof top unit controllers[130] | Evap. In Temp. UT Alarm |
| RDM Mercury AC and roof top unit controllers[130] | Under Temperature |
| RDM Mercury AC and roof top unit controllers[130] | Ut AL |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | Lo |
| Danfoss ETC (True cabinets)[142] | Lo |
| Carel PQ (True cabinets)[144] | LO |
| Dixell XR/XW (True cabinets)[145] | LA |
| LAE AR2/BR1/BIT25 and BR+/CD25/TM (True cabinets)[146] | Lo |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | AL1 |
| Taylor R160 frozen food dispenser[156] | LA |
| Dixell XR03CX/XR04CX (Hillphoenix display cases)[159] | LA |
| Carel MPXzero (Hillphoenix display cases)[160] | LO |
| Carel MPXzero (Hillphoenix display cases)[160] | LO2 |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | LO |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Case Temp Low Limit Exceeded |
| LAE AT1-5/AT2-5[166] | LO |
| Pego 202BASE electronic board[167] | EL |
| BAC Nexus modular hybrid cooler (NXF controls)[172] | Al_LvgWaterTempLow |
| BAC TrilliumSeries adiabatic cooler TRF[174] | 5 |
| LAE BR1-27/BR1-28/BR5-A/BR5-B/BD1-28/CD25[165] | LO |
The air temperature has been below the set low temperature limit for longer than the alarm delay.
Check: Check that the control cuts out and that the solenoid valve and contactor release. Compare the sensor with a thermometer.
Door open too long
| Controller | Code |
|---|---|
| Danfoss ERC 21X[1] | A04 |
| Danfoss EKC 202A/B/C[2] | A4 |
| Zanotti GM/GS[10] | OPd |
| Copeland EazyCool ZX (XCM25D)[5] | E66 |
| Carel ir33[11] | dor |
| Dixell XR60CX[12] | dA |
| Eliwell ID 974[13] | OPd |
| Carel Heos[18] | dr |
| Carel ir33+ VCC[20] | dor |
| Carel MPXone[21] | dor |
| Carel SmartCella / SmartCella 3PH[24] | dor |
| Danfoss AK-CC 450[32] | A4 |
| Danfoss AK-CC 550 / 550B[33] | A4 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | A04 |
| Danfoss AK-CC55 Water Loop[35] | A04 |
| Danfoss AK-CC 750[36] | Door open alarm |
| Danfoss Optyma control AK-RC 113[39] | Ed |
| Danfoss EKC 202D1[41] | A4 |
| Danfoss AK-RC 251[47] | Ad0 |
| Dixell XM669K/XM679K[50] | dA |
| Dixell XR06CX[51] | dA |
| Dixell XR35CX[52] | dA |
| Dixell XR460C[53] | dA |
| Dixell XR70CX[54] | dA |
| Dixell XW60K/XW60L[55] | dA |
| Dixell XWi70K[56] | dA |
| Secop SLV controller 105N46xx[81] | A04 |
| Pego ECP200 EXPERT PULSE[89] | Ed |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | Ed |
| RDM Mercury 3 Twin Coil[92] | door |
| Störk-Tronic ST121 / ST501 / ST551[93] | E5 |
| Evco EV3203[107] | id |
| Evco EVK214[109] | id |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | AOPn |
| Full Gauge TC-900E Log[118] | AOPn |
| Full Gauge MT-514E Faston[122] | AOPn |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | door |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | dor |
| Carel PQ (True cabinets)[144] | dOr |
| Dixell XR/XW (True cabinets)[145] | dA |
| LAE AR2/BR1/BIT25 and BR+/CD25/TM (True cabinets)[146] | do |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | OPd |
| Taylor C392/C393/C394 frozen beverage freezers[150] | Product Door Off |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | PRODUCT DOOR OFF |
| Taylor 736 soft serve freezer[153] | DOOR O. |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er18 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er18 |
| Dixell XR03CX/XR04CX (Hillphoenix display cases)[159] | dA |
| Carel MPXzero (Hillphoenix display cases)[160] | dor |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | dor |
| HTPG EcoNet enabled unit coolers[162] | T003 |
| LAE AT1-5/AT2-5[166] | DO |
| Pego 202BASE electronic board[167] | Ed |
| LAE BR1-27/BR1-28/BR5-A/BR5-B/BD1-28/CD25[165] | do |
| Taylor R280 fry dispenser[158] | Temperature flashingThe cabinet door is ajar; after 15 minutes the compressor stops until it is closed. (The manual does not give the colour.) Door symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-RC 251[47] | Icon door flashingDoor has been open longer than parameter A12. (The manual does not give the colour.) Door symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Staff BTX/BFX automatic batch freezers (BTX150, BFX150, BFX200, BFX201, BFX400, BFX600, BFX1000, BFX1500)[193] | Continuous beepThe lid of the freezing cylinder is open. |
| Carel MPXone[21] | Display reading flashing (door open too long)Door has been open longer than parameter Add: control restarts, light stays on, buzzer and alarm relay are activated. (The manual does not give the colour.) Door symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
The door contact has signalled an open door for longer than the set time.
Check: Close the door and check the door contact, its cable and the door alarm setting.
Condenser temperature too high
| Controller | Code |
|---|---|
| Danfoss ERC 21X[1] | A61 |
| Danfoss ERC 21X[1] | A80 |
| Danfoss Optyma Plus[4] | A80 |
| Zanotti GM/GS[10] | AH3 |
| Copeland EazyCool ZX (XCM25D)[5] | E46 |
| Carel ir33[11] | cht |
| Carel ir33[11] | CHt |
| Dixell XR60CX[12] | HA2 |
| Eliwell ID 974[13] | COH |
| Carel ir33+ VCC[20] | cht |
| Carel ir33+ VCC[20] | CHt |
| Carel SmartCella / SmartCella 3PH[24] | cht |
| Carel SmartCella / SmartCella 3PH[24] | CHt |
| Copeland Large ZX 22–30 HP[29] | E46 |
| Danfoss AK-CC55 Water Loop[35] | AA4 |
| Danfoss AK-PC 781A[37] | Air flow reduced cond. A |
| Danfoss EKC 202A/B/C[2] | A61 |
| Dixell XR35CX[52] | HA2 |
| Dixell XR70CX[54] | HA2 |
| Dixell XW60K/XW60L[55] | HA2 |
| Dixell XWi70K[56] | HA2 |
| Danfoss DHP heat pumps (DHP-A/AL/C/H/L)[76] | HIGH RETURN |
| NIBE F1255 ground source heat pump[78] | 162 |
| NIBE F1255 ground source heat pump[78] | 163 |
| Secop SLV controller 105N46xx[81] | A37 |
| RDM DMTouch / miniDM[91] | Cond N TD Alarm |
| Evco EV3203[107] | COH |
| Evco EV3203[107] | CSd |
| Evco EVK214[109] | CSd |
| Evco EV3 HP / EVD HP (heat pump)[110] | AHtr |
| Evco EV3 CHILL / HPRU (chiller, heat pump)[111] | AHtr |
| Thermia Atella / Robust[114] | HIGH RETURN |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | AC1 |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | AC2 |
| Full Gauge TC-900E Log[118] | AtC1 |
| Full Gauge TC-900E Log[118] | AtC2 |
| RDM Mercury AC and roof top unit controllers[130] | Cond. Out Temp. OT Alarm |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | PC 0A |
| ActronAir Nexus Touch Controller WTC-01[139] | PC0A |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | Con |
| Danfoss EETa (True cabinets, LED blink codes)[143] | 1+3 flashes |
| Dixell XR/XW (True cabinets)[145] | HA2 |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er13 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er13 |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | CHt |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | cht |
| LAE BR1-27/BR1-28/BR5-A/BR5-B/BD1-28/CD25[165] | HC |
The condenser sensor measures too high a temperature. With the block alarm (ERC 21X: A80) the compressor stops and the alarm must be reset manually.
Check: Clean the condenser and check the fan and the airflow. Reset only when the cause has been fixed.
Condensing or discharge pressure too high
| Controller | Code |
|---|---|
| Carel EVD evolution / EVD evolution twin[16] | HiTcond |
| Carel Heos[18] | HP |
| Carel pRack pR300[22] | ALB04 |
| Carel pRack pR300[22] | ALB21 |
| Carel pRack pR300[22] | ALW01 |
| Carel pRack pR300T (transcritical CO2)[23] | ALB21 |
| Carel µRack[25] | A14 |
| Carel µRack[25] | A27 |
| Carel µRack[25] | A28 |
| Copeland EazyCool ZX (XCM25D)[5] | E45 |
| Danfoss AK-PC 781A[37] | High pressure Pc |
| Danfoss AK-PC 782A/782B[38] | High pressure Pc |
| Danfoss EKE 1A/1B/1C/1D[43] | A989 |
| Danfoss Optyma iCO2[46] | A17 |
| Dixell XC645D[48] | F-HA |
| Carel µChiller[60] | A26 |
| Copeland CoreSense Diagnostics (UltraTech scroll)[66] | LED yellow 2 yellow ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (UltraTech scroll)[66] | LED red 2 red ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | F6 |
| LG Multi V 5 VRF outdoor units[77] | CH34 |
| Hussmann parallel rack / CO2 cascade (basic alarm package)[86] | High Discharge |
| Hussmann transcritical CO2 rack (rack controller alarms)[87] | High Discharge Pressure |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | DISCHARGE PRESSURE HIGH |
| Temperzone UC8 unit controller[100] | HP |
| Temperzone UC7 unit controller[101] | HP |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | 5 flashes red ●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | U1 |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Ud |
| Goodman DX20VC inverter condensing unit[105] | E13 |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | High Pressure Alarm |
| Hitachi multi-split heat pump[113] | 46 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | P20 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | P20 |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A27 |
| RDM Intuitive / Mercury pack and condenser controllers[131] | HP |
| RDM Intuitive / Mercury pack and condenser controllers[131] | hiPr |
| RDM Intuitive / Mercury pack and condenser controllers[131] | triP |
| RDM Intuitive Superpack / Transcritical Superpack[132] | HP |
| RDM Intuitive Superpack / Transcritical Superpack[132] | triP |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 69 |
| Temperzone UC6 unit controller[135] | 4 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E44 |
| ActronAir Aires and Advance 19–25 kW[137] | E44 |
| ActronAir Nexus Touch Controller WTC-01[139] | PH90 |
| True Ice TI/TCIM ice machines[147] | E6 |
| True Ice TI/TCIM ice machines[147] | E20 |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er08 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er08 |
| Copeland (CPC) E2 RX/BX/CX controller[163] | High Discharge Limit Exceeded |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Discharge Trip |
| Copeland (CPC) E2 RX/BX/CX controller[163] | ISD Discharge Pressure Trip |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red dark / yellow dark / green litHigh pressure switch open. Alarm symbol: green steady |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp B 6 flashesU1/Ud high pressure (63H) or overheating protection (pattern B = outdoor/other unit: lamp on for about 3 s, then the flashes). Alarm symbol: green ●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| IVT AirX air-to-water heat pump[175] | 5299High pressure caused by too little heating-water flow (air in the system, clogged particle filter or closed radiator thermostats). |
| IVT AirX air-to-water heat pump[175] | 5292Dirty or blocked outdoor air coil or a stopped fan, detected on high pressure transmitter JR1. |
| IVT AirX air-to-water heat pump[175] | 5298High pressure warning on JR1 caused by too little heating-water flow. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5292Dirty or blocked outdoor air coil or a stopped fan, detected on high pressure transmitter JR1. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5298High pressure warning on JR1 caused by too little heating-water flow. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5299High pressure alarm on JR1 caused by too little heating-water flow. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5640Condensing temperature above 65 °C, outdoor unit code 61 (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5641Condensing temperature above 65 °C, outdoor unit code 61 (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5298High pressure warning on JR1 caused by poor heating-water circulation. |
| IVT Geo 500/600 series ground source heat pump[177] | 5299High pressure alarm on JR1 caused by poor heating-water circulation. |
| IVT Geo 312/412 ground source heat pump[178] | 5298High pressure warning on JR1 caused by poor heating-water circulation. |
| IVT Geo 312/412 ground source heat pump[178] | 5299High pressure alarm on JR1 caused by poor heating-water circulation. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5292Dirty or blocked outdoor air coil or a stopped fan, detected on high pressure transmitter JR1. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5298High pressure warning on JR1 caused by too little heating-water flow. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5299High pressure alarm on JR1 caused by too little heating-water flow. |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 7 + Timer 3High pressure protection in cooling (code 24): check the outdoor fan, blocked condenser air, closed valves and overcharge. red + green ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 7 + Timer 3Abnormal pressure rise in cooling (14 on these models). green + orange ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 14Abnormal pressure rise in cooling on multi-zone RML models; the older UK guide lists an outdoor EEPROM fault. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 24High pressure protection in cooling: outdoor fan, blocked condenser air, closed valve or overcharge. |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | EE:00High pressure problem (listed only in the unknown-publisher list). |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation blinking + Timer 6High pressure protection. green + red ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu non-inverter outdoor unit PCB (older, two red LEDs)[189] | LED 1 8 + LED 2 steadyHigh pressure trip. red ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | A4High pressure abnormal (E.A4.1 sensor, E.A4.2 pressure switch): 3 high pressure stops within 60 min. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.A4.1High pressure abnormal: P2 stop (4.00 MPa or more from the sensor) 3 times within 60 min. Cooling: liquid-side service valve, outdoor fan, coil, ambient and recirculation, EEV1 and strainer, SV2, sensor, overcharge. Heating: gas-side valve, indoor EEVs and strainers. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | P2Stopped by high pressure protection: sensor 4.00 MPa or more (or pressure switch open at 4.2 MPa); restarts after 5 min below 3.50 MPa (switch: below 3.2 MPa). Three times in 60 min gives E.A4.1/E.A4.2. |
| Störk-Tronic ST121 / ST501 / ST551[93] | ST551 LED2 on (default)With factory settings LED2 on the ST551 shows a high-pressure alarm. (The manual does not give the colour.) Alarm symbol: red steady |
The condensing (or gas cooler) pressure measured by the transmitter is above the alarm limit.
Check: Check condenser fans, a dirty condenser, recirculating air, overcharge and non-condensables; compare the transmitter with a gauge.
CO2 gas cooler pressure or temperature
| Controller | Code |
|---|---|
| Carel pRack pR300T (transcritical CO2)[23] | ALB03 |
| Carel pRack pR300T (transcritical CO2)[23] | ALB04 |
| Danfoss EKC 326A[42] | A82 |
| Danfoss EKC 326A[42] | A83 |
| Danfoss EKC 326A[42] | A94 |
| RDM Intuitive Superpack / Transcritical Superpack[132] | gOt |
| RDM Intuitive Superpack / Transcritical Superpack[132] | gHPS |
| RDM Intuitive Superpack / Transcritical Superpack[132] | gLPS |
| RDM Intuitive Superpack / Transcritical Superpack[132] | gbHP |
The gas cooler outlet pressure or temperature in a transcritical CO2 system is outside its limits.
Check: Check gas cooler fans and cleanliness, the high pressure valve and its control, and the outdoor temperature.
Receiver pressure or level
| Controller | Code |
|---|---|
| Carel pRack pR300T (transcritical CO2)[23] | ALT18 |
| Danfoss AK-PC 781A[37] | Recv. High pressure alarm |
| Danfoss AK-PC 781A[37] | Recv. Low pressure alarm |
| Danfoss AK-PC 782A/782B[38] | Recv. High pressure alarm |
| Danfoss AK-PC 782A/782B[38] | Recv. Low pressure alarm |
| Danfoss AK-PC 782A/782B[38] | Rec. High liquid level alarm |
| Danfoss EKC 326A[42] | A84 |
| Danfoss EKC 326A[42] | A95 |
| Danfoss Optyma iCO2[46] | A85 |
| Hussmann parallel rack / CO2 cascade (basic alarm package)[86] | Low Liquid Level |
| Hussmann transcritical CO2 rack (rack controller alarms)[87] | Low Liquid Level |
| Hussmann transcritical CO2 rack (rack controller alarms)[87] | High Flash Tank Pressure |
| Hussmann transcritical CO2 rack (rack controller alarms)[87] | Low Flash Tank Pressure |
| Hussmann pumped liquid CO2 secondary system (E2 rack controller alarms)[88] | LOW RECEIVER LIQUID LEVEL SHUT DOWN |
| Hussmann pumped liquid CO2 secondary system (E2 rack controller alarms)[88] | HIGH CO2 RECEIVER PRESSURE |
| Hussmann pumped liquid CO2 secondary system (E2 rack controller alarms)[88] | LOW CO2 RECEIVER PRESSURE |
| RDM Intuitive Superpack / Transcritical Superpack[132] | rcHP |
| RDM Intuitive Superpack / Transcritical Superpack[132] | rcLP |
| RDM Intuitive Superpack / Transcritical Superpack[132] | rHIL |
| RDM Intuitive Superpack / Transcritical Superpack[132] | rLOL |
The receiver (flash tank) pressure or liquid level is too high or too low.
Check: Check the flash gas (bypass) valve and its control, the high pressure valve and the charge; at standstill check the auxiliary cooling.
High pressure or bypass valve fault (HPV/RPRV)
| Controller | Code |
|---|---|
| Carel pRack pR300T (transcritical CO2)[23] | ALT07 |
| Carel pRack pR300T (transcritical CO2)[23] | ALT08 |
The high pressure valve or the receiver bypass (flash gas) valve of a CO2 system does not control or is faulty.
Check: Check the valve coil, cable and driver, the signal from the controller and that the valve moves; compare with the pressure readings.
Four-way (reversing) valve fault
| Controller | Code |
|---|---|
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | EA |
| LG Multi V 5 VRF outdoor units[77] | CH151 |
| Temperzone UC8 unit controller[100] | F35 |
| Temperzone UC7 unit controller[101] | F35 |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | PL |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | P19 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | P19 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | S.590 |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp A 13 flashesPL refrigerant circuit abnormal (wireless: count flashes after self-check; pattern A = indoor unit, starts after about 2.5 s off). Alarm symbol: green ●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| IVT AirX air-to-water heat pump[175] | 5296Four-way valve fault; cooling mode is not possible. |
| IVT AirX air-to-water heat pump[175] | 5297Four-way valve fault; heating mode is not possible. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5296Four-way valve fault; cooling mode is not possible. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5297Four-way valve fault; heating mode is not possible. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5296Four-way valve fault; cooling mode is not possible. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5297Four-way valve fault; heating mode is not possible. |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 7 + Timer 4Four-way valve abnormal: the unit does not get the expected change between heating and cooling (code 2C). red + green ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 20 flashesFour-way valve fault. red ●●●●●●●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 2CFour-way valve abnormal. |
The unit sees that the four-way valve has not switched as commanded, or that the pressure difference between the high and low side stays too small, so the valve is probably stuck halfway, leaking internally or not powered.
Check: Check the coil voltage and coil resistance and the plug on the pilot valve. Compare discharge and suction pressures and feel the temperatures of the four pipes on the valve: a hot suction pipe or two equally warm pipes point to a valve stuck in the middle or leaking across. Try switching mode a few times with a good pressure difference; if it does not move, replace the valve.
Condenser temperature too low
| Controller | Code |
|---|---|
| Dixell XR60CX[12] | LA2 |
| Carel pRack pR300[22] | ALB03 |
| Carel µRack[25] | A13 |
| Dixell XC645D[48] | F-LA |
| Dixell XR35CX[52] | LA2 |
| Dixell XR70CX[54] | LA2 |
| Dixell XW60K/XW60L[55] | LA2 |
| Dixell XWi70K[56] | LA2 |
| Temperzone UC8 unit controller[100] | F43 |
| RDM Mercury AC and roof top unit controllers[130] | Cond. Out Temp. UT Alarm |
The condenser sensor has measured a temperature below the set low limit for longer than the alarm delay; depending on settings the compressor may be stopped.
Check: Check the condenser sensor position and reading, the condenser fan control and the outdoor temperature, and whether head pressure control is needed in cold weather.
Suction pressure too low
| Controller | Code |
|---|---|
| Carel EVD evolution / EVD evolution twin[16] | Low suction temperature |
| Carel EVD ice / EVD mini[17] | E4 |
| Carel Heos[18] | LSA |
| Carel Heos[18] | LP |
| Carel MPXone[21] | LSA |
| Carel pRack pR300[22] | ALB16 |
| Carel pRack pR300T (transcritical CO2)[23] | ALB16 |
| Carel µRack[25] | A15 |
| Copeland EXD-SH1/2[26] | AFE |
| Copeland EXD-SH1/2[26] | LOP |
| Copeland EazyCool ZX (XCM25D)[5] | E43 |
| Sanhua SEC60x[31] | LoP |
| Sanhua SEC60x[31] | FrE |
| Danfoss AK-PC 781A[37] | Low pressure P0 |
| Danfoss AK-PC 782A/782B[38] | Low pressure P0 |
| Danfoss AK-PC 782A/782B[38] | Low pressure Psuc-MT |
| Danfoss Optyma Plus[4] | A2 |
| Danfoss Optyma iCO2[46] | A2 |
| Dixell XC645D[48] | E01L |
| Dixell XC645D[48] | C1-LA |
| Dixell XEV12D[49] | LPL |
| Carel µChiller[60] | A27 |
| LG Multi V 5 VRF outdoor units[77] | CH35 |
| Hussmann transcritical CO2 rack (rack controller alarms)[87] | Low Suction Pressure |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | SUCTION PRESSURE LOW |
| Temperzone UC8 unit controller[100] | LP |
| Temperzone UC7 unit controller[101] | LP |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 1505 |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 1605 |
| Goodman DX20VC inverter condensing unit[105] | E15 |
| Hitachi multi-split heat pump[113] | 44 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | H06 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | H06 |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A06 |
| RDM Intuitive / Mercury pack and condenser controllers[131] | LP |
| RDM Intuitive / Mercury pack and condenser controllers[131] | LoPr |
| RDM Intuitive / Mercury pack and condenser controllers[131] | Sd |
| RDM Intuitive / Mercury pack and condenser controllers[131] | LoSh |
| RDM Intuitive Superpack / Transcritical Superpack[132] | LP |
| RDM Intuitive Superpack / Transcritical Superpack[132] | Sd |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 68 |
| Temperzone UC6 unit controller[135] | 3 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E42 |
| ActronAir Aires and Advance 19–25 kW[137] | E42 |
| True Ice TI/TCIM ice machines[147] | E32 |
| True Ice TI/TCIM ice machines[147] | E11 |
| True Ice TI/TCIM ice machines[147] | E13 |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Low Suction Limit Exceeded |
| Copeland (CPC) E2 RX/BX/CX controller[163] | ISD Suction Pressure Trip |
| alpha innotec WWB 190 DHW heat pump[169] | E7 |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red dark / yellow blink / green darkLow pressure switch open. Alarm symbol: yellow ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| IVT AirX air-to-water heat pump[175] | 5515Low evaporating pressure on transmitter JR0; first check that the outdoor fan and coil are not blocked. |
| IVT AirX air-to-water heat pump[175] | 5514Evaporating pressure JR0 too low: low outdoor temperature or too little air flow; clean the outdoor coil. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5514Evaporating pressure JR0 too low: low outdoor temperature or too little air flow; clean the outdoor coil. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5515Evaporating pressure JR0 too low; make sure there is enough air flow through the outdoor coil. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5666Evaporating pressure too low, LG code 35 (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5667Evaporating pressure too low, LG code 35 (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5514Low evaporating pressure on JR0; IVT points first to heating-side flow (thermostats, filter, air), check the brine side too. |
| IVT Geo 500/600 series ground source heat pump[177] | 5515Low evaporating pressure on JR0; IVT points first to heating-side flow (thermostats, filter, air), check the brine side too. |
| IVT Geo 312/412 ground source heat pump[178] | 5514Low evaporating pressure on JR0; IVT points first to heating-side flow (thermostats, filter, air), check the brine side too. |
| IVT Geo 312/412 ground source heat pump[178] | 5515Low evaporating pressure on JR0; IVT points first to heating-side flow (thermostats, filter, air), check the brine side too. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5514Evaporating pressure JR0 too low; clean the air filter and check the air flow (info). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5515Evaporating pressure JR0 too low; clean the air filter and check the air flow (alarm). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5666Evaporating pressure too low; check the air filter and the air flow (warning). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5667Evaporating pressure too low; check the air filter and the air flow (alarm). |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | A5Low pressure abnormal (E.A5.1): 5 low pressure stops within 3 h. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.A5.1Low pressure abnormal: P3 stop (0.05 MPa or less, or 0.10 MPa or less for 10 min) 5 times within 3 h; the unit locks out. Cooling: gas-side valve, indoor EEVs and strainers, SV2, sensor, leak. Heating: liquid-side valve, too low ambient, outdoor fan and coil, EEV1 and strainer. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | P3Stopped by low pressure protection: 0.05 MPa or less, or 0.10 MPa or less for 10 min; restarts after 3 min above 0.17 MPa. Five times in 3 h gives E.A5.1. |
| Störk-Tronic ST121 / ST501 / ST551[93] | ST551 LED3 on (default)With factory settings LED3 on the ST551 shows a low-pressure alarm. (The manual does not give the colour.) Alarm symbol: red steady |
The suction pressure or evaporating temperature measured by the transmitter is below the alarm limit.
Check: Troubleshoot as a low pressure trip: air flow, ice, refrigerant charge, restrictions and the expansion valve; compare the transmitter with a gauge.
Suction pressure too high
| Controller | Code |
|---|---|
| Carel pRack pR300[22] | ALB15 |
| Carel pRack pR300T (transcritical CO2)[23] | ALB15 |
| Carel µRack[25] | A16 |
| Danfoss AK-PC 781A[37] | High pressure P0 |
| Danfoss AK-PC 782A/782B[38] | High pressure P0 |
| Danfoss AK-PC 782A/782B[38] | High pressure Psuc-MT |
| Dixell XC645D[48] | C1-HA |
| Hussmann parallel rack / CO2 cascade (basic alarm package)[86] | High Suction |
| Hussmann transcritical CO2 rack (rack controller alarms)[87] | High Suction Pressure |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | SUCTION PRESSURE HIGH |
| Temperzone UC8 unit controller[100] | HI-SL |
| Temperzone UC7 unit controller[101] | HI-SL |
| Temperzone UC8 unit controller[100] | F42 |
| Copeland (CPC) E2 RX/BX/CX controller[163] | High Suction Limit Exceeded |
The suction pressure measured by the transmitter is above the alarm limit, for example from high load or too little compressor capacity.
Check: Check the load, the compressor capacity steps and whether the compressors pump; compare the transmitter with a gauge.
Pressure switch has tripped
| Controller | Code |
|---|---|
| Danfoss Optyma Plus[4] | A17 |
| Copeland EazyCool ZX (XCM25D)[5] | E40 |
| Copeland EazyCool ZX (XCM25D)[5] | E41 |
| Carel μC2SE[8] | HP1 |
| Carel μC2SE[8] | LP1 |
| Dixell XW270L/XW271L[9] | PAL |
| Zanotti GM/GS[10] | HPA |
| Zanotti GM/GS[10] | LPA |
| Zanotti GM/GS[10] | PA |
| Carel ir33[11] | LP |
| Dixell XR60CX[12] | CA |
| Eliwell ID 974[13] | nPA |
| Eliwell ID 974[13] | PAL |
| Carpigiani AES PSP[15] | AL11 |
| Carel ir33+ VCC[20] | LP |
| Carel pRack pR300[22] | ALB01 |
| Carel pRack pR300[22] | ALB02 |
| Carel pRack pR300T (transcritical CO2)[23] | ALB01 |
| Carel pRack pR300T (transcritical CO2)[23] | ALB02 |
| Carel pRack pR300T (transcritical CO2)[23] | ALC92 |
| Carel SmartCella / SmartCella 3PH[24] | LP |
| Carel µRack[25] | A10 |
| Carel µRack[25] | A12 |
| Copeland EazyCool ZX (XCM25D)[5] | L40 |
| Copeland Large ZX 22–30 HP[29] | E40 |
| Copeland Large ZX 22–30 HP[29] | L40 |
| Copeland Large ZX 22–30 HP[29] | E41 |
| Heatcraft Beacon II[30] | E7 |
| Heatcraft Beacon II[30] | SHTDN |
| Danfoss AK-PC 781A[37] | Comp. x disch. Press. Cut out |
| Danfoss AK-PC 782A/782B[38] | Comp. x disch. Press. Cut out |
| Danfoss Optyma iCO2[46] | A97 |
| Dixell XC645D[48] | E0L1 |
| Dixell XC645D[48] | E0H |
| Dixell XM669K/XM679K[50] | PAL |
| Dixell XR35CX[52] | CA |
| Dixell XR70CX[54] | CA |
| Dixell XW60K/XW60L[55] | CA |
| Dixell XWi70K[56] | CA |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 34 |
| Carel µC2SE for process chiller[59] | HP1 |
| Carel µC2SE for process chiller[59] | LP1 |
| Carel µChiller[60] | A25 |
| Carel µChiller[60] | A29 |
| Copeland CoreSense Diagnostics (scroll AC)[64] | LED yellow 2 yellow ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (scroll AC)[64] | LED red 2 red ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (UltraTech scroll)[66] | LED yellow 3 yellow ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (UltraTech scroll)[66] | LED red 3 red ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED yellow 2 yellow ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Danfoss CDS303/CDS803[69] | A68 |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | E3 |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | E4 |
| Danfoss DHP heat pumps (DHP-A/AL/C/H/L)[76] | HIGH PRESSURE ERROR |
| Danfoss DHP heat pumps (DHP-A/AL/C/H/L)[76] | LOW PRESSURE ERROR |
| LG Multi V 5 VRF outdoor units[77] | CH24 |
| NIBE F1255 ground source heat pump[78] | 50 |
| NIBE F1255 ground source heat pump[78] | 51 |
| NIBE F1255 ground source heat pump[78] | 58 |
| Störk-Tronic ST121 / ST501 / ST551[93] | E6 |
| Störk-Tronic ST121 / ST501 / ST551[93] | E7 |
| Goodman DX20VC inverter condensing unit[105] | E24 |
| Evco EV3 HP / EVD HP (heat pump)[110] | AHP1 |
| Evco EV3 HP / EVD HP (heat pump)[110] | ALP1 |
| Evco EV3 CHILL / HPRU (chiller, heat pump)[111] | AHP1 |
| Evco EV3 CHILL / HPRU (chiller, heat pump)[111] | ALP1 |
| Evco EV3 MVC / EVD MVC (air handling)[112] | AL07 |
| Evco EV3 MVC / EVD MVC (air handling)[112] | AL08 |
| Hitachi multi-split heat pump[113] | 02 |
| Thermia Atella / Robust[114] | LOW PRESSURE ERROR |
| Thermia Atella / Robust[114] | HIGH PRESSURE ERROR |
| Copeland Electronic Unit Controller[116] | HP |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | P04 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | P04 |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | 21 |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A23 |
| RDM Mercury AC and roof top unit controllers[130] | HP/LP Fault |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 90 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E09 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E11 |
| ActronAir Aires and Advance 19–25 kW[137] | E9 |
| ActronAir Aires and Advance 19–25 kW[137] | E11 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | PC 03 |
| ActronAir Nexus Touch Controller WTC-01[139] | PC03 |
| Dixell XR/XW (True cabinets)[145] | PAL |
| Taylor frozen beverage freezers C300, C302, C303/C314, 345/346/349/355[149] | CHK REFRIG SYS PSI |
| Taylor C392/C393/C394 frozen beverage freezers[150] | Compressor Hi/Lo Pres Cut out |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | COMPRESSOR HPCO |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | HPCO H/C |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | HO |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | HPCO COMPRESSOR |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | COMPRESSOR HPCO |
| Taylor R200 fry dispenser[157] | Error 6 |
| Taylor R280 fry dispenser[158] | Err 6 |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | LP |
| alpha innotec BWP 190S/260S DHW heat pump[168] | Er6 |
| alpha innotec WWB 190 DHW heat pump[169] | E6 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | S.302 |
| Danfoss Optyma iCO2[46] | Display S34Safe stop: a pressure or temperature safety switch on DI1 has opened. Alarm symbol: green steady |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D801 yellow (3 s on / 0.5 s off)Current error: High pressure switch error (21). Alarm symbol: yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Dixell XC645D[48] | LED LP steadyLow-pressure switch alarm. (The manual does not give the colour.) Alarm symbol: red steady |
| Dixell XC645D[48] | LED HP steadyHigh-pressure switch alarm. (The manual does not give the colour.) Alarm symbol: red steady |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault G-onHigh-pressure switch open (red off, yellow off, green on). Alarm symbol: green steady |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault Y-blinkLow-pressure switch open (red off, yellow blink, green off). Alarm symbol: yellow ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| IVT AirX air-to-water heat pump[175] | 5507High pressure switch MR1 warning: heating-water flow too low, e.g. a closed or partly closed heating system. |
| IVT AirX air-to-water heat pump[175] | 5508High pressure switch MR1 tripped: heating-water flow too low, e.g. a closed or partly closed heating system. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5507High pressure switch MR1 warning: heating-water flow too low, e.g. a closed or partly closed heating system. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5508High pressure switch MR1 tripped: heating-water flow too low. |
| IVT Geo 500/600 series ground source heat pump[177] | 5507High pressure switch MR1 tripped from a flow problem on the heating side (filter, closed thermostats, air). |
| IVT Geo 500/600 series ground source heat pump[177] | 5508High pressure switch MR1 tripped from a flow problem on the heating side (filter, closed thermostats, air). |
| IVT Geo 312/412 ground source heat pump[178] | 5507High pressure switch MR1 tripped from a flow problem on the heating side (filter, closed thermostats, air). |
| IVT Geo 312/412 ground source heat pump[178] | 5508High pressure switch MR1 tripped from a flow problem on the heating side (filter, closed thermostats, air). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5507High pressure switch MR1 warning: heating-water flow too low, e.g. a closed or partly closed heating system. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5508High pressure switch MR1 tripped: heating-water flow too low. |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 7 + Timer 5Pressure switch open (code 16); clears by itself when the pressure is normal again: check condenser air flow, outdoor fan and charge. red + green ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 7 + Timer 6High pressure switch open (16). green + orange ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 9 flashesHigh pressure switch 1 open. red ●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 10 flashesHigh pressure switch 2 open. red ●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 16Pressure switch open. |
| Fujitsu wall-mounted multi indoor units (older, UK; two-stage lamp code)[186] | Red blinking + Green 3, test button: Red 2 + Green blinkingPressure switch open. red + green ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 9–30 (older, one red LED)[187] | LED red 8Pressure switch open. red ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 36–54 (older, one red LED)[188] | LED red 9Pressure switch open. red ●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter multi outdoor unit AOY30 (older, LEDs A–D)[190] | LED A–D 8 flashesPressure switch open (as models 9–30). red ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter multi outdoor unit AOY30 (older, LEDs A–D)[190] | LED A–D 9 flashesPressure switch A open. red ●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter multi outdoor unit AOY30 (older, LEDs A–D)[190] | LED A–D 10 flashesPressure switch B open. red ●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red rapid + Green 6 short (F)High or low pressure switch has tripped. red + green ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | C1 45High pressure switch PS(H)1 on circuit 1 has opened (4.15 MPa off, 3.2 MPa on, automatic reset): check the discharge pressure, a dirty or blocked condenser, the condenser fan and the air inlet temperature. |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | C2 45High pressure switch PS(H)2 on circuit 2 has opened (4.15 MPa off, 3.2 MPa on, automatic reset): check the discharge pressure, a dirty or blocked condenser, the condenser fan and the air inlet temperature. |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | C1 47Low pressure switch PS(L)1 on circuit 1 has opened (0.40 MPa off, 0.70 MPa on, automatic reset): check the suction pressure, refrigerant charge, air filter and evaporator air flow. |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | C2 47Low pressure switch PS(L)2 on circuit 2 has opened (0.40 MPa off, 0.70 MPa on, automatic reset): check the suction pressure, refrigerant charge, air filter and evaporator air flow. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.86.4High pressure switch found open at power-on. Check the switch connector and wiring and that the switch closes (it resets at about 3.2 MPa); then the main PCB. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.A4.2High pressure protection 1: the high pressure switch (opens at 4.2 MPa) tripped 3 times within 60 min. Same checks as E.A4.1 plus the check valve at the oil separator outlet and the switch itself. |
| Thermia Atella / Robust[114] | Symbol squareThe operating pressure switch has tripped or the hot gas temperature has reached its maximum. (The manual does not give the colour.) Symbol: yellow steady |
A high or low pressure switch has opened. After several trips in a short time many controllers lock the compressor until the alarm is reset manually.
Check: Measure the pressure and troubleshoot the high or low pressure. Reset only when the cause has been found.
Pump-down fault
| Controller | Code |
|---|---|
| Carel ir33[11] | Pd |
| Carel ir33[11] | AtS |
| Carel ir33+ VCC[20] | Pd |
| Carel ir33+ VCC[20] | AtS |
| Carel SmartCella / SmartCella 3PH[24] | Pd |
| Carel SmartCella / SmartCella 3PH[24] | AtS |
| Danfoss AK-RC 251[47] | Pd |
| Danfoss AK-RC 251[47] | LP |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | Pd |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | AtS |
The compressor did not reach the low-pressure switch within the maximum pump-down time, or it had to restart because the suction pressure rose again while the liquid line valve was closed.
Check: Check that the solenoid valve on the liquid line closes tightly, that the low-pressure switch is set correctly and that the compressor pumps; repeated restarts usually point to a leaking valve.
Discharge temperature too high
| Controller | Code |
|---|---|
| Danfoss Optyma Plus[4] | A96 |
| Copeland EazyCool ZX (XCM25D)[5] | E44 |
| Danfoss VLT FC 103[14] | W19 |
| Carel Heos[18] | Hid |
| Copeland Stream condensing units (Next Gen CoreSense)[27] | 3 flashes orange ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland ZSI scroll condensing units[28] | LED4 red steady |
| Copeland EazyCool ZX (XCM25D)[5] | L44 |
| Copeland Large ZX 22–30 HP[29] | E44 |
| Copeland Large ZX 22–30 HP[29] | L44 |
| Danfoss AK-PC 781A[37] | Comp. x disch. Temp cut out |
| Danfoss AK-PC 781A[37] | High disch. temp. SdA |
| Danfoss AK-PC 782A/782B[38] | Comp. x disch. Temp cut out |
| Danfoss AK-PC 782A/782B[38] | High disch. temp. SdA |
| Danfoss Optyma Plus Module B Plus (P02)[45] | Y1-R1 yellow ● → red ● · 1 s on, 1 s off · 1 s between colours · pause 3 s (timing assumed, not stated in the manual) |
| Danfoss Optyma Plus Module B Plus (P02)[45] | Y1-R2 yellow ● → red ●● · 1 s on, 1 s off · 1 s between colours · pause 3 s (timing assumed, not stated in the manual) |
| Danfoss Optyma iCO2[46] | A96 |
| Dixell XC645D[48] | dtL |
| Carel µChiller[60] | A46 |
| Copeland Digital Compressor Controller[61] | 2 flashes red ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland PerformanceAlert diagnostic module[62] | 1 flash yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Protection (Discus)[63] | LED yellow 3 yellow ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Protection (Discus)[63] | LED red 3 red ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland compressor electronics communications (20–40 ton scroll)[65] | LED red 4 red ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED yellow 1 yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED red 1 red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | F3 |
| LG Multi V 5 VRF outdoor units[77] | CH32 |
| NIBE F1255 ground source heat pump[78] | 55 |
| NIBE F1255 ground source heat pump[78] | 155 |
| Kriwan INT69 F Diagnose[94] | LED red 3 / orange 1 red ●●● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 PYF Diagnose[95] | LED red 3 / orange 1 red ●●● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 PYF Diagnose[95] | LED red 3 / orange 2 red ●●● → orange ●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 YF Diagnose[98] | LED red 3 / orange 1 red ●●● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 YF Diagnose[98] | LED red 3 / orange 2 red ●●● → orange ●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | DISCHARGE TEMPERATURE HIGH |
| Temperzone UC8 unit controller[100] | HI-t |
| Temperzone UC7 unit controller[101] | HI-t |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 1504 |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | 3 flashes red ●●● · 0.5 s on, 0.5 s off · pause 2.5 s |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | U2 |
| Goodman DX20VC inverter condensing unit[105] | E22 |
| Evco EV3 HP / EVD HP (heat pump)[110] | AdS1 |
| Evco EV3 CHILL / HPRU (chiller, heat pump)[111] | AdS1 |
| Hitachi multi-split heat pump[113] | 08 |
| Hitachi multi-split heat pump[113] | 23 |
| Copeland Electronic Unit Controller[116] | DLT |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | P03 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | P03 |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | 1E |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A25 |
| RDM Intuitive / Mercury pack and condenser controllers[131] | di Ot |
| RDM Intuitive Superpack / Transcritical Superpack[132] | dtFt |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 78 |
| Temperzone UC6 unit controller[135] | 9 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E06 |
| ActronAir Aires and Advance 19–25 kW[137] | E6 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | PC 02 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | PC 06 |
| Copeland (CPC) E2 RX/BX/CX controller[163] | ISD Discharge Temp Trip |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | S.286 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | F.823 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | S.303 |
| Vaillant aroSTOR plus VWL B/BM 200/6, 260/6[171] | P82 |
| Vaillant aroSTOR plus VWL B/BM 200/6, 260/6[171] | E45 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Running lamp 3 + timer flashingCompressor top temperature, IPM temperature or high pressure protection (PC 02). (The manual does not give the colour.) Alarm symbol: green ●●● → orange ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Kriwan INT69 F Diagnose[94] | LED green 3 / orange 1Warning: temperature input 1 (e.g. discharge) is above its permitted value. Symbol: green ●●● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 YF Diagnose[98] | LED green 3 / orange 1Warning: temperature input 1 is above its permitted value. Symbol: green ●●● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 YF Diagnose[98] | LED green 3 / orange 2Warning: temperature input 2 is above its permitted value. Symbol: green ●●● → orange ●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D800+D801+D803 yellow (3 s on / 0.5 s off)Current error: Discharge temperature error (1E). Alarm symbol: yellow ● → yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp B 5 flashesU2 high discharge temperature / 49C tripped / low refrigerant (pattern B = outdoor/other unit: lamp on for about 3 s, then the flashes). Alarm symbol: green ●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| IVT AirX air-to-water heat pump[175] | 5310Discharge (hot gas) temperature too high (warning). |
| IVT AirX air-to-water heat pump[175] | 5311Discharge (hot gas) temperature too high (alarm). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5310Discharge (hot gas) temperature too high (warning). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5311Discharge (hot gas) temperature too high (alarm). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5618Discharge (hot gas) temperature too high, LG code 32 (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5619Discharge (hot gas) temperature too high, LG code 32 (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5310Discharge (hot gas) temperature too high, often temporary (warning). |
| IVT Geo 500/600 series ground source heat pump[177] | 5311Discharge (hot gas) temperature too high (alarm). |
| IVT Geo 312/412 ground source heat pump[178] | 5310Discharge (hot gas) temperature too high, often temporary (warning). |
| IVT Geo 312/412 ground source heat pump[178] | 5311Discharge (hot gas) temperature too high (alarm). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5310Discharge (hot gas) temperature too high (warning). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5311Discharge (hot gas) temperature too high (alarm). |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 7 + Timer 2Discharge temperature protection (code 0F): look for closed service valves, low charge or leaks, and restrictions in the line set. red + green ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 7 + Timer 6Compressor body above about 108 °C (code 2b): check service valves, EEV, charge, compressor thermistor, outdoor fan and a dirty outdoor coil. red + green ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 7 + Timer 2Discharge temperature too high (0F). green + orange ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 18 flashesDischarge temperature too high. red ●●●●●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 19 flashesCompressor temperature too high. red ●●●●●●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 0FDischarge temperature too high: closed service valves, gas shortage, leak or restriction. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 2bCompressor temperature too high (about 108 °C on the 2019 models). |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | EF:00Discharge temperature too high, usually gas shortage or contamination in the pipework. |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation blinking + Timer 7Discharge or compressor temperature too high. green + red ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu non-inverter outdoor unit PCB (older, two red LEDs)[189] | LED 1 7 + LED 2 steadyDischarge temperature too high. red ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu non-inverter outdoor unit PCB (older, two red LEDs)[189] | LED 1 9 + LED 2 steadyCompressor temperature too high. red ●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red rapid + Green 7 short (F)Discharge temperature too high. red + green ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | A1Discharge temperature abnormal (E.A1.1): discharge reached 115 °C twice within 40 min. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | A3Compressor temperature abnormal (E.A3.1): compressor body reached 110 °C twice within 40 min. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.A1.1Discharge temperature abnormal: P1 stop (115 °C or more) twice within 40 min; the unit locks out. Check the service valve (gas side in cooling, liquid side in heating), the EEVs and strainers, outdoor fan and coil, TH1 and the charge (leak). Reset by power cycle and error reset. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.A3.1Compressor temperature abnormal: P4 stop (compressor body 110 °C or more) twice within 40 min; the unit locks out. Same checks as E.A1.1, with TH10 instead of TH1. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | P1Stopped by discharge temperature protection: discharge 115 °C or more; restarts after 3 min once it is 80 °C or less. Twice within 40 min gives E.A1.1. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | P4Stopped by compressor temperature protection: compressor body 110 °C or more; restarts after 3 min with discharge 80 °C or less. Twice within 40 min gives E.A3.1. |
| Danfoss DHP heat pumps (DHP-A/AL/C/H/L)[76] | Square symbol by the hot gas (delivery pipe) temperatureAppears when the discharge pipe temperature has reached the set DELIVERY PIPE limit. (The manual does not give the colour.) Symbol: yellow steady |
The sensor on the discharge pipe measures a temperature above the limit, and the compressor is stopped for protection.
Check: Measure superheat, suction and high pressure and troubleshoot high discharge temperature.
Low superheat
| Controller | Code |
|---|---|
| Carel EVD evolution / EVD evolution twin[16] | LowSH |
| Carel EVD ice / EVD mini[17] | E3 |
| Carel Heos[18] | LSh |
| Carel MPXone[21] | LSH |
| Carel pRack pR300[22] | ALW10 |
| Carel pRack pR300[22] | ALE02 |
| Carel pRack pR300T (transcritical CO2)[23] | ALT15 |
| Copeland EXD-SH1/2[26] | LSH |
| Copeland EazyCool ZX (XCM25D)[5] | E50 |
| Copeland Large ZX 22–30 HP[29] | E50 |
| Heatcraft Beacon II[30] | E6 |
| Heatcraft Beacon II[30] | SUPLO |
| Sanhua SEC60x[31] | LSH |
| Danfoss AK-PC 781A[37] | Low superheat section A |
| Danfoss AK-PC 782A/782B[38] | Low superheat section A |
| Danfoss EKE 1A/1B/1C/1D[43] | A987 |
| Danfoss EKE 100[44] | A25 |
| Dixell XC645D[48] | PrSH |
| Dixell XC645D[48] | ALSH |
| Dixell XEV12D[49] | LSH |
| Dixell XM669K/XM679K[50] | LSH |
| Carel µC2SE for process chiller[59] | SH1 |
| Carel µChiller[60] | A35 |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | F4 |
| LG Multi V 5 VRF outdoor units[77] | CH150 |
| Hussmann transcritical CO2 rack (rack controller alarms)[87] | Superheat Alarm |
| Pego ECP200 EXPERT PULSE[89] | LSH |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | SUCTION SUPERHEAT LOW |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | DISCHARGE SUPERHEAT LOW |
| Temperzone UC8 unit controller[100] | Lo-dSH |
| Temperzone UC7 unit controller[101] | Lo-dSH |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 1502 |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | 7 flashes red ●●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | U7 |
| Goodman DX20VC inverter condensing unit[105] | E21 |
| Hitachi multi-split heat pump[113] | 07 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | P13 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Superheat Low |
| RDM Intuitive Superpack / Transcritical Superpack[132] | ShUt |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Low Pack Superheat |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D801+D802+D804 yellow (3 s on / 0.5 s off)Current error: PMV (expansion valve) error, superheat -8 K or less. Alarm symbol: yellow ● → yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp B 10 flashesU7 low discharge superheat (pattern B = outdoor/other unit: lamp on for about 3 s, then the flashes). Alarm symbol: green ●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| IVT AirX air-to-water heat pump[175] | 5366Refrigerant superheat too low (warning). |
| IVT AirX air-to-water heat pump[175] | 5367Refrigerant superheat too low (alarm). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5366Refrigerant superheat too low (warning). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5367Refrigerant superheat too low (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5366Low superheat; IVT links it to poor heating-side flow (thermostats, air, filter). |
| IVT Geo 500/600 series ground source heat pump[177] | 5367Low superheat; IVT links it to poor heating-side flow (thermostats, air, filter). |
| IVT Geo 312/412 ground source heat pump[178] | 5366Low superheat; IVT links it to poor heating-side flow (thermostats, air, filter). |
| IVT Geo 312/412 ground source heat pump[178] | 5367Low superheat; IVT links it to poor heating-side flow (thermostats, air, filter). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5366Refrigerant superheat too low (warning). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5367Refrigerant superheat too low (alarm). |
Superheat at the evaporator outlet has been below the low limit for longer than the delay, so liquid may reach the compressor.
Check: Check the superheat with gauge and thermometer, the sensor position and insulation, and whether the valve closes; a valve that hangs open or a sensor reading too warm are common causes.
High superheat
| Controller | Code |
|---|---|
| Carel Heos[18] | HSh |
| Copeland EXD-SH1/2[26] | HSH |
| Sanhua SEC60x[31] | HSH |
| Danfoss AK-PC 781A[37] | High superheat suction A |
| Danfoss AK-PC 782A/782B[38] | High superheat suction A |
| Danfoss EKE 1A/1B/1C/1D[43] | A988 |
| Danfoss EKE 100[44] | A24 |
| Dixell XEV12D[49] | HSH |
| Dixell XM669K/XM679K[50] | HSH |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | SUCTION TEMPERATURE HIGH |
| Temperzone UC8 unit controller[100] | Hi-dSH |
| Temperzone UC7 unit controller[101] | HI-dSH |
| RDM Intuitive Superpack / Transcritical Superpack[132] | ShOt |
| Temperzone UC8 unit controller[100] | HI-SL |
| Temperzone UC7 unit controller[101] | HI-SL |
| Temperzone UC7 unit controller[101] | Hi-dSH |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D800+D802+D804 yellow (3 s on / 0.5 s off)Current error: PMV (expansion valve) error, superheat 20 K or more. Alarm symbol: yellow ● → yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| IVT Geo 500/600 series ground source heat pump[177] | 5543Superheat above the optimum, usually temporary (warning). |
| IVT Geo 312/412 ground source heat pump[178] | 5543Superheat above the optimum, usually temporary (warning). |
Superheat has been above the high limit for longer than the delay, so the evaporator is underfed.
Check: Check refrigerant charge, sight glass, filter drier and valve capacity, and that the valve opens as commanded.
Maximum operating pressure (MOP)
| Controller | Code |
|---|---|
| Carel EVD evolution / EVD evolution twin[16] | MOP |
| Carel EVD ice / EVD mini[17] | E1 |
| Carel Heos[18] | MOP |
| Carel ir33+ VCC[20] | Eht |
| Carel MPXone[21] | MOP |
| Carel pRack pR300[22] | ALE02 |
| Sanhua SEC60x[31] | MoP |
| Danfoss EKE 1A/1B/1C/1D[43] | A991 |
| Danfoss EKE 100[44] | A22 |
| Dixell XEV12D[49] | MOP |
| Dixell XM669K/XM679K[50] | MOP |
| Carel µC2SE for process chiller[59] | nO1 |
| Carel µChiller[60] | A37 |
| Pego ECP200 EXPERT PULSE[89] | MOP |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | MOP Alarm |
| Dixell XEV12D[49] | LED MOP alarm onSuction pressure is above the Maximum Operating Pressure threshold. Alarm symbol: red steady |
| Copeland EXD-SH1/2[26] | Superheat value blinkingThe superheat reading blinks while the controller is limiting in MOP mode (suction pressure above MOP). (The manual does not give the colour.) Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
The evaporating pressure or temperature is above the MOP limit, so the valve driver throttles to protect the compressor.
Check: Check the load (warm start-up, defrost return, open doors) and the MOP setting; a lasting alarm can point to a valve that does not close or too high a suction pressure.
Low operating pressure (LOP)
| Controller | Code |
|---|---|
| Carel EVD evolution / EVD evolution twin[16] | LOP |
| Carel EVD ice / EVD mini[17] | E2 |
| Carel Heos[18] | LOP |
| Carel MPXone[21] | LOP |
| Carel pRack pR300[22] | ALE02 |
| Danfoss EKE 1A/1B/1C/1D[43] | A990 |
| Danfoss EKE 100[44] | A23 |
| Dixell XEV12D[49] | LOP |
| Dixell XM669K/XM679K[50] | LOP |
| Carel µC2SE for process chiller[59] | LO1 |
| Carel µChiller[60] | A36 |
| Pego ECP200 EXPERT PULSE[89] | LOP |
| Dixell XEV12D[49] | LED low pressure alarm onSuction pressure has fallen to the LOP threshold. Alarm symbol: red steady |
The evaporating pressure or temperature is below the LOP limit, so the valve driver opens to avoid a low pressure trip or freezing.
Check: Check air flow and ice on the evaporator, refrigerant charge and the LOP setting.
Injection problem
| Controller | Code |
|---|---|
| Danfoss AK-CC 550 / 550B[33] | A10 |
| Danfoss AK-CC 750[36] | Injection problem |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Superheat problem |
The controller cannot keep the superheat under control with the electronic expansion valve, for example because the valve is too small or too large, the refrigerant supply is poor or the evaporator sensors give misleading values.
Check: Check the liquid supply to the valve (sight glass, subcooling, filter drier), the valve size and orifice, and that the pressure transmitter and outlet sensor are mounted correctly and read plausible values.
Expansion valve out of capacity
| Controller | Code |
|---|---|
| Danfoss EKE 1A/1B/1C/1D[43] | A986 |
| Danfoss EKE 100[44] | A26 |
The expansion valve has stayed close to fully open for longer than the delay without reaching the superheat reference, so the evaporator is underfed.
Check: Look for flash gas in the liquid line (undercharge, too little subcooling), a blocked filter drier, too low condensing pressure, and check that the valve type set in the controller matches the valve and that it is large enough.
Flash gas at the expansion valve
| Controller | Code |
|---|---|
| Danfoss AK-CC 550 / 550B[33] | AD flashgas |
| Danfoss AK-CC 750[36] | AD – Flash gas detect |
The controller has seen signs for a long time that the liquid reaching the expansion valve contains gas, which cuts capacity and makes the superheat unstable.
Check: Check subcooling and the sight glass before the valve, refrigerant charge, a clogged filter drier or a long or rising liquid line, and the liquid line pressure drop.
Valve motor or valve driver fault
| Controller | Code |
|---|---|
| Carel EVD evolution / EVD evolution twin[16] | EEV motor error |
| Carel EVD evolution / EVD evolution twin[16] | Driver B disconnected |
| Carel EVD ice / EVD mini[17] | E5 |
| Carel EVD ice / EVD mini[17] | E8 |
| Carel MPXone[21] | bLo |
| Carel MPXone[21] | Edc |
| Carel pRack pR300[22] | ALE01 |
| Carel pRack pR300[22] | ALE05 |
| Copeland EXD-SH1/2[26] | 1Π- |
| Copeland EXD-SH1/2[26] | 2Π- |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | A43 |
| Danfoss EKC 326A[42] | A43 |
| Danfoss EKE 1A/1B/1C/1D[43] | E126 |
| Danfoss EKE 100[44] | A39 |
| Danfoss EKE 100[44] | A40 |
| Danfoss EKE 100[44] | A41 |
| Carel µC2SE for process chiller[59] | EU1 |
| Carel µChiller[60] | A38 |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | A9 |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | E9 |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 1608 |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | 20 |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A07 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Stepper Fault |
| RDM Intuitive Superpack / Transcritical Superpack[132] | SCPU |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | F.582 |
| Danfoss AK-PC 781A[37] | Stepper module LED red flashingFault on the valve motor or its wiring. Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-PC 782A/782B[38] | AK-XM 208C LED red flashFault on the stepper motor or its connection. Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D803+D804 yellow (3 s on / 0.5 s off)Current error: PMV leakage error, unit A (20). Alarm symbol: yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D800+D803+D804 yellow (3 s on / 0.5 s off)Current error: PMV leakage error, unit B (20). Alarm symbol: yellow ● → yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D801+D803+D804 yellow (3 s on / 0.5 s off)Current error: PMV leakage error, unit C (20). Alarm symbol: yellow ● → yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D800+D801+D803+D804 yellow (3 s on / 0.5 s off)Current error: PMV leakage error, unit D (20). Alarm symbol: yellow ● → yellow ● → yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D802+D803+D804 yellow (3 s on / 0.5 s off)Current error: PMV leakage error, unit E (20). Alarm symbol: yellow ● → yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Danfoss EKE 1A/1B/1C/1D[43] | Valve LEDs red and green flashingValve-related alarm. Alarm symbol: red + green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Danfoss EKE 100[44] | Valve LED red/green alternatingOpen circuit on the valve stepper motor or valve driver overheating; check valve wiring. Symbol: red + green flashing fast |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 9AOutdoor expansion valve coil error, EEV1 or EEV2 (E.9A.1/E.9A.2). |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.9A.1Outdoor expansion valve EEV1 coil open or short (CN116). Check the plug, the wires, the coil (46 ± 4 Ω per phase at 20 °C) and 12 V DC from the main PCB with the coil unplugged. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.9A.2Outdoor expansion valve EEV2 coil open or short (CN117). Same checks as E.9A.1. |
The stepper or pulse valve, its coil, cable or the valve driver is faulty, offline or not calibrated.
Check: Measure the coil resistance and the cable, check the driver supply and communication, and let the driver re-home the valve.
Compressor motor protection
| Controller | Code |
|---|---|
| Copeland EazyCool ZX (XCM25D)[5] | E28 |
| Carel μC2SE[8] | tC1 |
| Carpigiani AES PSP[15] | AL01 |
| Carpigiani AES PSP[15] | AL02 |
| Carel pRack pR300T (transcritical CO2)[23] | ALC91 |
| Copeland Stream condensing units (Next Gen CoreSense)[27] | 4 flashes orange ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland EazyCool ZX (XCM25D)[5] | E23 |
| Copeland EazyCool ZX (XCM25D)[5] | L23 |
| Copeland Large ZX 22–30 HP[29] | E23 |
| Copeland Large ZX 22–30 HP[29] | L23 |
| Copeland Large ZX 22–30 HP[29] | E28 |
| Danfoss AK-PC 781A[37] | Comp. x over current cut out |
| Danfoss AK-PC 781A[37] | Comp. x motor prot. cut out |
| Danfoss AK-PC 782A/782B[38] | Comp. x motor prot. cut out |
| Carel µC2SE for process chiller[59] | tP |
| Carel µC2SE for process chiller[59] | tC1 |
| Carel µChiller[60] | A30 |
| Copeland Digital Compressor Controller[61] | 3 flashes red ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland PerformanceAlert diagnostic module[62] | LED red red steady |
| Copeland PerformanceAlert diagnostic module[62] | 5 flashes yellow ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Protection (Discus)[63] | LED yellow 2 yellow ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (scroll AC)[64] | LED yellow 5 yellow ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (scroll AC)[64] | LED red (steady) red steady |
| Copeland CoreSense Diagnostics (scroll AC)[64] | LED red 5 red ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland compressor electronics communications (20–40 ton scroll)[65] | LED red 1 red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (UltraTech scroll)[66] | LED red solid red steady |
| Copeland CoreSense Diagnostics (UltraTech scroll)[66] | LED yellow 5 yellow ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (UltraTech scroll)[66] | LED red 5 red ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED green 5 green ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | E5 |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | E6 |
| Danfoss DHP heat pumps (DHP-A/AL/C/H/L)[76] | MOTOR P ERROR |
| Pego ECP200 EXPERT PULSE[89] | Ec |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | Ec |
| Kriwan INT69 PYF Diagnose[95] | LED red 6 / orange 1 red ●●●●●● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | COMPRESSOR MOTOR CURRENT HIGH |
| Temperzone UC8 unit controller[100] | OL |
| Temperzone UC7 unit controller[101] | OL |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 4108 |
| Evco EV3 HP / EVD HP (heat pump)[110] | AtC1 |
| Evco EV3 CHILL / HPRU (chiller, heat pump)[111] | APMP |
| Evco EV3 CHILL / HPRU (chiller, heat pump)[111] | At1 |
| Evco EV3 CHILL / HPRU (chiller, heat pump)[111] | AtC1 |
| Evco EV3 MVC / EVD MVC (air handling)[112] | AL11 |
| Thermia Atella / Robust[114] | MOTOR P ERROR |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | H04 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | H04 |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | 1C |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A22 |
| RDM Mercury AC and roof top unit controllers[130] | Comp. Overload Fault |
| Taylor 736 soft serve freezer[153] | THERMAL |
| Copeland (CPC) E2 RX/BX/CX controller[163] | ISD Motor Temp Trip |
| Copeland (CPC) E2 RX/BX/CX controller[163] | ISD Internal Line Break |
| Pego 202BASE electronic board[167] | Ec |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D800 yellow (3 s on / 0.5 s off)Current error: Compressor case thermostat error (check code 1C). Alarm symbol: yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Carel µC2SE for process chiller[59] | Icon alarm red flashingGeneral overload (tP): pumps, compressors and fans are stopped. Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel SmartCella / SmartCella 3PH[24] | LED COMPRESSOR yellow off with demand (3PH panel)No power at the compressor terminals; check motor protector QM1 if cooling is demanded. Compressor symbol: yellow ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | C1 08The internal thermostat of compressor 1 has opened (factory value 130 °C off, 108 °C on, automatic reset): check the thermostat circuit, suction superheat, charge and supply voltage. |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | C2 08The internal thermostat of compressor 2 has opened (130 °C off, 108 °C on, automatic reset): check the thermostat circuit, suction superheat, charge and supply voltage. |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | C1 39Overcurrent on compressor motor 1, measured by current transformer CT1: measure the running current, the voltage and phase balance, and the high pressure. |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | C2 39Overcurrent on compressor motor 2, measured by current transformer CT2: measure the running current, the voltage and phase balance, and the high pressure. |
The built-in thermal protector or the overcurrent protection in the compressor circuit has tripped.
Check: Let the motor cool down, measure voltage and current and find out why the protection tripped.
Beater motor overload or locked beater
| Controller | Code |
|---|---|
| Taylor frozen beverage freezers C300, C302, C303/C314, 345/346/349/355[149] | BEATER OVERLOAD |
| Taylor frozen beverage freezers C300, C302, C303/C314, 345/346/349/355[149] | Beater Over Current |
| Taylor C392/C393/C394 frozen beverage freezers[150] | Beater Overload |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | BEATER OVERLOAD |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | BEATER OVLD H/C |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | BO |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | BEATER OVERLOAD |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | BEATER LOCKED |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er07 |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er14 |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er21 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er07 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er14 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er21 |
| Staff BTX/BFX automatic batch freezers (BTX150, BFX150, BFX200, BFX201, BFX400, BFX600, BFX1000, BFX1500)[193] | OL2Agitator motor overload: the product is too stiff (density or time set too high for the batch) or the scrapers drag; free the agitator with the vat defrost, then press reset. |
| Staff BTX/BFX automatic batch freezers (BTX150, BFX150, BFX200, BFX201, BFX400, BFX600, BFX1000, BFX1500)[193] | OH2The agitator motor's internal thermal protection has tripped: let the motor cool, check the density setting and the scrapers, then press reset. |
The beater (dasher) motor of an ice cream, shake or frozen drink machine has drawn too much current or its overload protection has tripped, often because the product has frozen too hard, the viscosity setting is too high, the scraper blades are worn or the motor or drive is faulty.
Check: Let the product thaw and reset; check the viscosity or consistency setting, mix and refrigeration (product frozen too hard), scraper blades, drive belt and beater motor current.
Oil level or oil pressure
| Controller | Code |
|---|---|
| Carel Heos[18] | dLP |
| Carel pRack pR300[22] | ALB06 |
| Carel pRack pR300T (transcritical CO2)[23] | ALB06 |
| Carel pRack pR300T (transcritical CO2)[23] | ALC94 |
| Copeland Stream condensing units (Next Gen CoreSense)[27] | 1 flash orange ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland Large ZX 22–30 HP[29] | E56 |
| Copeland Large ZX 22–30 HP[29] | L56 |
| Danfoss AK-PC 781A[37] | Comp. x oil pressure cut out |
| Danfoss AK-PC 781A[37] | Low oil level comp. x |
| Danfoss AK-PC 782A/782B[38] | Comp. x oil pressure cut out |
| Copeland CoreSense Protection (Discus)[63] | LED green 1 green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Protection (Discus)[63] | LED red 1 red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| LG Multi V 5 VRF outdoor units[77] | CH116 |
| Hussmann parallel rack / CO2 cascade (basic alarm package)[86] | Oil Failure |
| Hussmann transcritical CO2 rack (rack controller alarms)[87] | Oil Failure |
| Hussmann transcritical CO2 rack (rack controller alarms)[87] | Oil Reservoir Low |
| Hussmann transcritical CO2 rack (rack controller alarms)[87] | Oil Separator High |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | ⊿OP LOW |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | OIL LEVEL LOW |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 1559 |
| Evco EV3 CHILL / HPRU (chiller, heat pump)[111] | AOi1 |
| Castel 5650E/5658E electronic oil level regulator (R744)[123] | LED red on |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | H07 |
| RDM Intuitive Superpack / Transcritical Superpack[132] | Oil1–Oil9 |
| RDM Intuitive Superpack / Transcritical Superpack[132] | OilO |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 15 |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 133 |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 134 |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Oil Failure Occurred |
| Copeland (CPC) E2 RX/BX/CX controller[163] | ISD Low Oil Warning |
| Copeland (CPC) E2 RX/BX/CX controller[163] | ISD Oil Pressure Lockout |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | Signal lamp H2 (oil supply fault) onOil supply fault has tripped (lamp wired per wiring diagram). (The manual does not give the colour.) Alarm symbol: red steady |
| Bitzer VARIPACK FMY+/FMU+ .. FSW+ (frequency inverter)[58] | Lamp P04Panel lamp in the wiring example: oil supply fault. (The manual does not give the colour.) Alarm symbol: red steady |
The oil level is low or the oil pressure difference is too small.
Check: Check the oil level in the sight glass, oil return and separator, oil management valves and the oil pressure sensor or switch.
Oil temperature out of range
| Controller | Code |
|---|---|
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | OIL SUPPLY TEMPERATURE HIGH |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | SEPARATOR OIL TEMPERATURE LOW |
The oil temperature in the supply line or the oil separator of a screw compressor is too high or too low.
Check: High: check the oil cooler (water/refrigerant flow, fouling, thermostatic valve) and the discharge temperature. Low: check the separator heater and look for liquid refrigerant reaching the compressor, which dilutes the oil.
Oil filter clogged
| Controller | Code |
|---|---|
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | OIL FILTER |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | FINE FILTER |
The pressure drop across the oil filter or fine filter is above the limit, so the compressor may not get enough oil.
Check: Read the pressure before and after the filter, replace the filter element and look at the oil condition (sample or analysis) to find the source of the dirt.
Compressor fault or lock-out
| Controller | Code |
|---|---|
| Carel Heos[18] | GEA |
| Carel pRack pR300[22] | ALC01 |
| Carel µRack[25] | A01 |
| Copeland EazyCool ZX (XCM25D)[5] | E24 |
| Heatcraft Beacon II[30] | A3 |
| Heatcraft Beacon II[30] | STRUP |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | A19 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | a12 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | a13 |
| Danfoss AK-CC55 Water Loop[35] | A19 |
| Danfoss AK-PC 781A[37] | Common compr. Safety cutout |
| Danfoss AK-PC 781A[37] | Comp. x FCD safety error |
| Danfoss AK-PC 782A/782B[38] | Common compr. Safety cutout |
| Danfoss Optyma control AK-RC 113[39] | Ec |
| Danfoss Optyma Plus[4] | A98 |
| Danfoss Optyma iCO2[46] | H28 |
| Dixell XC645D[48] | EA1 |
| Dixell XC645D[48] | EA2 |
| Dixell XC645D[48] | EA3 |
| Dixell XC645D[48] | EA4 |
| Dixell XC645D[48] | FC01 |
| Dixell XC645D[48] | LC01 |
| Carel µChiller[60] | A48 |
| Copeland PerformanceAlert diagnostic module[62] | 2 flashes yellow ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (UltraTech scroll)[66] | LED red 6 red ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (UltraTech scroll)[66] | LED red 7 red ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Danfoss CDS303/CDS803[69] | A49 |
| Secop SLV controller 105N46xx[81] | A81 |
| Secop SLV controller 105N46xx[81] | E80 |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | E80 |
| Hussmann parallel rack / CO2 cascade (basic alarm package)[86] | Compressor Failure |
| Hussmann transcritical CO2 rack (rack controller alarms)[87] | Compressor Failure |
| Hussmann transcritical CO2 rack (rack controller alarms)[87] | Compressor VFD Alarm |
| RDM DMTouch / miniDM[91] | Pack Fail Shutdown |
| Temperzone UC8 unit controller[100] | F39 |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | UE |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | 11 flashes red ●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s |
| Goodman DX20VC inverter condensing unit[105] | E17 |
| Hitachi multi-split heat pump[113] | 39 |
| Hitachi multi-split heat pump[113] | 43 |
| Hitachi multi-split heat pump[113] | EE |
| Thermia Calibra[115] | Class A |
| Copeland Electronic Unit Controller[116] | HPL |
| Copeland Electronic Unit Controller[116] | DLL |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | H01 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | H01 |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | 1F |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A18 |
| RDM Mercury AC and roof top unit controllers[130] | Compressor Lock Alarm |
| RDM Mercury AC and roof top unit controllers[130] | Cloc |
| RDM Intuitive / Mercury pack and condenser controllers[131] | CP |
| RDM Intuitive / Mercury pack and condenser controllers[131] | Stg1–Stg5 |
| RDM Intuitive / Mercury pack and condenser controllers[131] | Co 1–Co 5 |
| RDM Intuitive Superpack / Transcritical Superpack[132] | St 1–St 16 |
| RDM Intuitive Superpack / Transcritical Superpack[132] | StC 1–StC 16 |
| RDM Intuitive Superpack / Transcritical Superpack[132] | Inv 1–Inv 3 |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | Modbus Dev Locked |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 72 |
| Temperzone UC6 unit controller[135] | F |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E30 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E104 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | PC 04 |
| Danfoss ETC (True cabinets)[142] | E4 |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | UCF |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Rack Failure Occurred |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Proof Failure Occurred |
| Copeland (CPC) E2 RX/BX/CX controller[163] | ISD Compressor Module Failure |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | S.280 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | F.817 |
| Carel µRack[25] | Icon compressor + ALARM flashingCompressor alarm, e.g. compressor thermal overload. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red blink / yellow dark / green litCompressor non-synchronism: speed deviates from the set frequency for 2 s. Alarm symbol: red ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Running lamp 5 + timer flashingInverter compressor drive error (PC 04). (The manual does not give the colour.) Alarm symbol: green ●●●●● → orange ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D800+D801 yellow (3 s on / 0.5 s off)Current error: Compressor system error (1C). Alarm symbol: yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D800+D802 yellow (3 s on / 0.5 s off)Current error: Compressor breakdown (1F). Alarm symbol: yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Bitzer VARIPACK FMY+/FMU+ .. FSW+ (frequency inverter)[58] | Lamp P05Panel lamp in the wiring example: compressor fault. (The manual does not give the colour.) Alarm symbol: red steady |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | Light block Timer blinkingOutdoor compressor-related fault or protective shutdown (H01–H25: breakdown, lock-up, low-pressure drop, oil level …). (Operation and Ready off.) (The manual does not give the colour.) Compressor symbol: yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault R-blink G-onCompressor out of synchronism: running frequency deviates for 2 s (red blink, yellow off, green on). Alarm symbol: red ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| IVT AirX air-to-water heat pump[175] | 5350Compressor control fault, usually a power cut during operation so the compressor could not ramp down normally (warning). |
| IVT AirX air-to-water heat pump[175] | 5351Compressor control fault, usually a power cut during operation so the compressor could not ramp down normally (alarm). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5350Compressor control fault, usually a power cut during operation so the compressor could not ramp down normally (warning). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5351Compressor control fault, usually a power cut during operation so the compressor could not ramp down normally (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5350Compressor running out of step (asynchronous), probably after a power cut (warning). |
| IVT Geo 500/600 series ground source heat pump[177] | 5351Compressor running out of step (asynchronous) (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5903Compressor motor fault, usually temporary. |
| IVT Geo 312/412 ground source heat pump[178] | 5350Compressor running out of step (asynchronous), probably after a power cut (warning). |
| IVT Geo 312/412 ground source heat pump[178] | 5351Compressor running out of step (asynchronous) (alarm). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5350Compressor control fault, usually a power cut during operation so the compressor could not ramp down normally (warning). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5351Compressor control fault, usually a power cut during operation so the compressor could not ramp down normally (alarm). |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 13 flashesCompressor control fault (the compressor does not follow the inverter). red ●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation blinking + Timer 13Compressor fault. green + red ●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wall-mounted multi indoor units (older, UK; two-stage lamp code)[186] | Red blinking + Green 5, test button: Red 5 + Green blinkingInverter fault group; after the test button: compressor fault. red + green ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter multi outdoor unit AOY30 (older, LEDs A–D)[190] | LED A–D 14 flashesCompressor fault. red ●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | C1 40The current transformer CT1 for compressor 1 is not connected or gives no signal: check the CT1 plug and wiring on the PCB. |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | C2 40The current transformer CT2 for compressor 2 is not connected or gives no signal: check the CT2 plug and wiring on the PCB. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 95Compressor motor loss of synchronisation (E.95.5). Check the inverter PCB and compressor (lock). |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.95.5Compressor motor loss of synchronisation 5 times in a row. Check the inverter PCB (IPM) and the compressor for lock. |
The controller has stopped or locked out a compressor (several trips, start failure, safety chain or compressor module).
Check: Read which safety stopped it, check the compressor protection module, the safety chain and the reason for repeated trips before resetting.
Compressor runs too long
| Controller | Code |
|---|---|
| Copeland CoreSense Diagnostics (scroll AC)[64] | LED yellow 1 yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (UltraTech scroll)[66] | LED yellow 1 yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | ALrC |
| Full Gauge TC-900E Log[118] | ALrC |
| Full Gauge MT-514E Faston[122] | ALrC |
| RDM Intuitive / Mercury pack and condenser controllers[131] | Increase LED flashing |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | LEA |
| Danfoss EETa (True cabinets, LED blink codes)[143] | 3+1 flashes |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | COMP ON TOO LONG |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | COMP ON TOO LONG |
| Taylor 736 soft serve freezer[153] | TIME OUT |
| HTPG EcoNet enabled unit coolers[162] | A108 |
The compressor has run without a break for far longer than normal at full load, which usually means the system cannot reach its set point.
Check: Check the refrigerant charge and look for leaks, check that the evaporator fan runs and the coil is not iced or blocked, check the expansion valve and the filter drier, and check the thermostat setting and wiring.
Cooling too slow or not cooling
| Controller | Code |
|---|---|
| True Ice TI/TCIM ice machines[147] | E22 |
| Taylor frozen beverage freezers C300, C302, C303/C314, 345/346/349/355[149] | BARREL NOT COOLING |
| Taylor R200 fry dispenser[157] | Error 5 |
| Taylor R280 fry dispenser[158] | Err 5 |
The controller has seen that the product or cylinder temperature did not fall as expected within a set time after cooling started, so the refrigeration does not deliver its capacity.
Check: Check the condenser and its fan, refrigerant charge, expansion device, solenoid or hot gas valve and compressor; in ice cream machines also the scraper blades and mix.
Compressor short cycling
| Controller | Code |
|---|---|
| Copeland PerformanceAlert diagnostic module[62] | 3 flashes yellow ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (scroll AC)[64] | LED yellow 3 yellow ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (scroll AC)[64] | LED red 3 red ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland compressor electronics communications (20–40 ton scroll)[65] | LED green 3 green ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland compressor electronics communications (20–40 ton scroll)[65] | LED red 3 red ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Communications (13–15 ton scroll)[67] | LED green 3 green ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Communications (13–15 ton scroll)[67] | LED red 3 red ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED green 3 green ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Hussmann transcritical CO2 rack (rack controller alarms)[87] | Cycles Exceeded |
| Kriwan INT69 PYF Diagnose[95] | LED red 5 / orange 5 red ●●●●● → orange ●●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 YF Diagnose[98] | LED red 5 / orange 5 red ●●●●● → orange ●●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 74 |
| Kriwan INT69 YF Diagnose[98] | LED green 5 / orange 5Warning: the permitted number of starts (switching frequency) has been exceeded. Compressor symbol: green ●●●●● → orange ●●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
The compressor starts and stops too often, with very short run times, so the module counts the starts and warns or locks out.
Check: Check the thermostat or controller differential and set point, the pressure switch settings and the refrigerant charge; add an anti-short-cycle timer if the control lacks one.
Compressor contactor or control circuit fault
| Controller | Code |
|---|---|
| Copeland Digital Compressor Controller[61] | 8 flashes red ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland PerformanceAlert diagnostic module[62] | 8 flashes yellow ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (scroll AC)[64] | LED red 9 red ●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (UltraTech scroll)[66] | LED yellow 8 yellow ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (UltraTech scroll)[66] | LED red 10 red ●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED green 8 green ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Taylor R200 fry dispenser[157] | Error 7 |
| Taylor R280 fry dispenser[158] | Err 7 |
| Copeland (CPC) E2 RX/BX/CX controller[163] | ISD Welded Contactor |
| Copeland CoreSense Communications (13–15 ton scroll)[67] | LED yellow 8Current in the S and R windings without a demand signal for 15 s (welded contactor). Alarm symbol: yellow ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED yellow solidRun demand is present but no compressor current is detected (contactor, motor protector or supply). Compressor symbol: yellow steady |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 4 + Timer 3The outdoor unit still answers more than 2 min after the indoor main relay switched off, so the relay is probably welded (PCB fault). red + green ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
The module sees motor current without a run demand (welded contactor), or too much current in the contactor coil circuit it switches.
Check: Isolate the power and check the contactor contacts for welding or pitting, measure the coil and its wiring for shorts, and replace the contactor if it does not open.
Compressor outside its operating envelope
| Controller | Code |
|---|---|
| Carel µChiller[60] | A42 |
| Carel µChiller[60] | A45 |
| LG Multi V 5 VRF outdoor units[77] | CH36 |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | ⊿P LOW |
| Temperzone UC8 unit controller[100] | CRH |
| Goodman DX20VC inverter condensing unit[105] | E44 |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 4 |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 6 |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 8 |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 10 |
| Temperzone UC8 unit controller[100] | CRL |
| Temperzone UC8 unit controller[100] | diFF-P |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E43 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E45 |
| ActronAir Aires and Advance 19–25 kW[137] | E43 |
| ActronAir Aires and Advance 19–25 kW[137] | E45 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | PC 0L |
| alpha innotec WWB 190 DHW heat pump[169] | E8 |
| alpha innotec WWB 190 DHW heat pump[169] | E10 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | S.304 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | S.306 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | S.308 |
| IVT AirX air-to-water heat pump[175] | 5513Condensing temperature too high, outside the working range; check the water flow and lower the heating curve and the hot water setting. |
| IVT AirX air-to-water heat pump[175] | 5512Condensing temperature outside the control range, likely low outdoor temperature combined with high load. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5512Condensing temperature outside the control range, likely low outdoor temperature combined with high load. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5513Condensing temperature too high, probably at low outdoor temperature. |
| IVT Geo 500/600 series ground source heat pump[177] | 5512Condensing temperature outside the compressor envelope, usually temporary. |
| IVT Geo 500/600 series ground source heat pump[177] | 5513Condensing too high in relation to the evaporating temperature. |
| IVT Geo 312/412 ground source heat pump[178] | 5512Condensing temperature outside the compressor envelope, usually temporary. |
| IVT Geo 312/412 ground source heat pump[178] | 5513Condensing too high in relation to the evaporating temperature. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5512Condensing temperature outside the control range, likely low outdoor temperature combined with high load. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5513Condensing temperature too high, probably at low outdoor temperature. |
The evaporating and condensing pressures put the compressor (often a variable speed BLDC or inverter scroll) outside the operating limits set by its manufacturer, for example too high a compression ratio or too small a pressure difference, for longer than the delay, so the controller stops it.
Check: Compare the suction and discharge pressures with the compressor envelope: look for high head pressure (dirty condenser, fan fault, overcharge), very low suction pressure (low charge, low water flow, iced or fouled evaporator) or too small a pressure difference at low load, and check that the pressure transmitters read correctly.
Capacity slide valve fault
| Controller | Code |
|---|---|
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | CAPACITY NO DOWN |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | LOW SLIDE VALVE POSITION UNDER/OVER RANGE |
The capacity slide valve of a screw compressor does not move as commanded, or its position signal is outside the expected range.
Check: Check the load/unload solenoid valves and their coils, the position potentiometer or transmitter and its calibration, and the oil pressure that moves the slide.
Overcurrent at the drive output
| Controller | Code |
|---|---|
| Danfoss VLT FC 103[14] | A13 |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 3 |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 5 |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 7 |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 10 |
| Danfoss CDS303/CDS803[69] | A13 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A13 |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | E8 |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | L5 |
| LG Multi V 5 VRF outdoor units[77] | CH21 |
| LG Multi V 5 VRF outdoor units[77] | CH29 |
| NIBE F1255 ground source heat pump[78] | 453 |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 4210 |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 4250 |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | UP |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | 2 flashes red ●● · 0.5 s on, 0.5 s off · pause 2.5 s |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | UP |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | U6 |
| Goodman DX20VC inverter condensing unit[105] | E34 |
| Hitachi multi-split heat pump[113] | 48 |
| Hitachi multi-split heat pump[113] | 52 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | P26 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | P26 |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | 14 |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A15 |
| Temperzone UC8 unit controller[100] | F101 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E26 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E60 |
| ActronAir Aires and Advance 19–25 kW[137] | E26 |
| ActronAir Aires and Advance 19–25 kW[137] | E60 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | PC 00 |
| ActronAir UltraSlim 2 ducted split system[140] | EB |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er53 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er53 |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | 14 flashes |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red lit / yellow lit / green blinkPFC input over-current protection. Alarm symbol: red ● → yellow ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red lit / yellow blink / green blinkPFC module (IGBT) peak current protection. Alarm symbol: red ● → yellow ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red blink / yellow blink / green blinkCompressor phase over-current protection. Alarm symbol: red ● → yellow ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | Fan LED red 14xPeak current error: motor drawing too much current. Fan symbol: red ●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Running lamp 7 + timer flashingIPM/IGBT overcurrent (PC 00) or low pressure protection (PC 03); the table uses 7 flashes for both, so read the code. (The manual does not give the colour.) Alarm symbol: green ●●●●●●● → orange ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D801+D802 yellow (3 s on / 0.5 s off)Current error: Driving element short circuit (14). Alarm symbol: yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | 1 flashOvercurrent cut-out 3 times within 1 min of start (unit stopped), or frequency drop by current protection while running. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off · pause 2.5 s |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp B 2 flashesUP compressor overcurrent interruption (pattern B = outdoor/other unit: lamp on for about 3 s, then the flashes). Alarm symbol: green ●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp B 9 flashesU6 compressor overcurrent or power module fault (pattern B = outdoor/other unit: lamp on for about 3 s, then the flashes). Alarm symbol: green ●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault R-on Y-on G-blinkPFC input overcurrent (red on, yellow on, green blink). Alarm symbol: red ● → yellow ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault R-blink Y-blink G-blinkCompressor phase overcurrent (red blink, yellow blink, green blink). Alarm symbol: red ● → yellow ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| IVT AirX air-to-water heat pump[175] | 5524Overcurrent in the compressor inverter; a single trip after a power cut can be false, a recurring one points to the inverter or compressor. |
| IVT AirX air-to-water heat pump[175] | 5354Inverter output current to the compressor too high (warning). |
| IVT AirX air-to-water heat pump[175] | 5355Inverter output current to the compressor too high (alarm). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5354Inverter output current to the compressor too high (warning). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5355Inverter output current to the compressor too high (alarm). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5600Outdoor unit code 21; IVT gives no detail, on LG-built outdoor units this code usually means an inverter peak-current (IPM) trip. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5601Outdoor unit code 21; IVT gives no detail, on LG-built outdoor units this code usually means an inverter peak-current (IPM) trip. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5602Outdoor unit code 22; IVT gives no detail, on LG-built outdoor units this code usually means input current too high. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5603Outdoor unit code 22; IVT gives no detail, on LG-built outdoor units this code usually means input current too high. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5612LG outdoor unit code 27 (info); IVT gives no detail, usually a fault or overcurrent in the PFC (input) stage. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5613LG outdoor unit code 27 (alarm); IVT gives no detail, usually a fault or overcurrent in the PFC (input) stage. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5616Compressor current too high, LG code 29 (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5617Compressor current too high, LG code 29 (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5354Compressor overcurrent, probably after a power cut (warning). |
| IVT Geo 500/600 series ground source heat pump[177] | 5355Inverter output current to the compressor too high (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5523Overcurrent in the PFC (input) stage of the inverter; check that every phase is connected (warning). |
| IVT Geo 500/600 series ground source heat pump[177] | 5524Overcurrent in the PFC (input) stage of the inverter (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5906Short heavy overload of the compressor motor, usually temporary (info). |
| IVT Geo 500/600 series ground source heat pump[177] | 5987Short heavy overload of the compressor motor (alarm). |
| IVT Geo 312/412 ground source heat pump[178] | 5354Compressor overcurrent, probably after a power cut (warning). |
| IVT Geo 312/412 ground source heat pump[178] | 5355Inverter output current to the compressor too high (alarm). |
| IVT Geo 312/412 ground source heat pump[178] | 5523Overcurrent in the PFC (input) stage of the inverter; check that every phase is connected (warning). |
| IVT Geo 312/412 ground source heat pump[178] | 5524Overcurrent in the PFC (input) stage of the inverter (alarm). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5354Inverter output current to the compressor too high (warning). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5355Inverter output current to the compressor too high (alarm). |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 5 + Timer 2Inverter power module (IPM) protection from too high current (code 17): check that the outdoor fan runs, that air can reach the coil, and the refrigerant charge. red + green ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 5 + Timer 2Outdoor inverter power module (IPM) fault or overcurrent (17). green + orange ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 12 flashesOvercurrent in the outdoor unit. red ●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 14 flashesInverter power module (IPM) fault. red ●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 17Inverter power module (IPM) protection. |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation blinking + Timer 10Inverter power module (IPM) fault. green + red ●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wall-mounted multi indoor units (older, UK; two-stage lamp code)[186] | Red blinking + Green 5, test button: Red 2 + Green blinkingInverter fault group; after the test button: IPM fault. red + green ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 9–30 (older, one red LED)[187] | LED red 10Current trip (overcurrent). red ●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 36–54 (older, one red LED)[188] | LED red 12Inverter power module (IPM) fault. red ●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter multi outdoor unit AOY30 (older, LEDs A–D)[190] | LED A–D 12 flashesInverter power module (IPM) fault. red ●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 94Trip detection: repeated overcurrent after start (E.94.1). Check outdoor air flow, inverter PCB, compressor and SV2 coil. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.94.1Trip detection: overcurrent after start-up 5 times in a row (count resets if no new trip within 40 s of restart). Check outdoor air flow (fan, dirty coil, recirculation, high ambient), the inverter PCB, the compressor and the SV2 coil. |
The output current has exceeded the drive's peak limit, for example from a blocked or seized motor, a sudden load step or a motor that is too large for the drive.
Check: Switch off, then check that the compressor or fan turns freely, that the motor size matches the drive and that the motor data and ramp times are set correctly.
Drive overloaded (current or torque limit)
| Controller | Code |
|---|---|
| Danfoss VLT FC 103[14] | A9 |
| Danfoss VLT FC 103[14] | A12 |
| Carel ir33+ VCC[20] | UCF |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 6 |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 8 |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 9 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A9 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | W59 |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | I_Limit |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED orange 1 orange ● · 0.25 s on, 0.25 s off · pause 3 s |
| Danfoss VLT FC 103[14] | W59 |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | L8 |
| LG Multi V 5 VRF outdoor units[77] | CH22 |
| NIBE F1255 ground source heat pump[78] | 441 |
| NIBE F1255 ground source heat pump[78] | 455 |
| Danfoss CDS303/CDS803[69] | A12 |
| Secop BD electronic units (BD35F/BD50F/BD35K/BD80CN, 101N0212/0340/0390/0420/0510/0650)[80] | 4 flashes red ●●●● · 0.25 s on, 0.25 s off · pause 2.25 s |
| Secop SLV controller 105N46xx[81] | A82 |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 4240 |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | LED red steady red steady |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | LED red fast red flashing fast (2 Hz) |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E47 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E99 |
| ActronAir Aires and Advance 19–25 kW[137] | E47 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | PC 08 |
| ActronAir Nexus Touch Controller WTC-01[139] | PC08 |
| Copeland (CPC) E2 RX/BX/CX controller[163] | VS Inverter Fail |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red blink / yellow dark / green blinkCompressor IPM module protection (low drive voltage or IPM over-current). Alarm symbol: red ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Running lamp 1 + timer flashingCurrent overload protection (PC 08). (The manual does not give the colour.) Alarm symbol: green ● → orange ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED orange 3Warning: the power limiter is reducing output. Fan symbol: orange ●●● · 0.25 s on, 0.25 s off · pause 3 s |
| Bitzer VARIPACK FMY+/FMU+ .. FSW+ (frequency inverter)[58] | Symbol overloadOverload: output current is above the nominal motor current. (The manual does not give the colour.) Symbol: white steady |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault R-on Y-blink G-blinkPFC module (IGBT) peak-current protection (red on, yellow blink, green blink). Alarm symbol: red ● → yellow ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault R-blink G-blinkCompressor IPM module protection (low drive voltage or high IPM current) (red blink, yellow off, green blink). Alarm symbol: red ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| IVT Geo 500/600 series ground source heat pump[177] | 5902Compressor motor overload, possibly from low voltage between phase and neutral. |
| IVT Geo 500/600 series ground source heat pump[177] | 5990Compressor motor overloaded; check fuses and the supply voltage. |
The drive has delivered more than its rated current or the set torque limit for too long, so it limits the speed or trips to protect itself.
Check: Check the load on the compressor or fan (high condensing pressure, dirty condenser, liquid in the compressor, stiff bearings) and that the drive is sized for the motor; check the motor data and the current and torque limits.
Motor overload (calculated, ETR)
| Controller | Code |
|---|---|
| Danfoss VLT FC 103[14] | A10 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A10 |
The drive's electronic thermal model calculates that the motor has run above its rated current for so long that it is too hot.
Check: Check that the motor rated current is set correctly in the drive and that the motor is not overloaded; at low speed check that the motor still gets enough cooling.
Motor thermistor tripped
| Controller | Code |
|---|---|
| Danfoss VLT FC 103[14] | A11 |
| Copeland Stream condensing units (Next Gen CoreSense)[27] | 2 flashes orange ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland compressor electronics communications (20–40 ton scroll)[65] | LED red 2 red ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Communications (13–15 ton scroll)[67] | LED red 1 red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Communications (13–15 ton scroll)[67] | LED red 2 red ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A11 |
| Kriwan INT69 F Diagnose[94] | LED red 1 / orange 1 red ● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 F Diagnose[94] | LED red 1 / orange 4 red ● → orange ●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 PYF Diagnose[95] | LED red 1 / orange 1 red ● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 PYF Diagnose[95] | LED red 1 / orange 4 red ● → orange ●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 UY Diagnose[96] | LED red 1 / orange 1 red ● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 UY Diagnose[96] | LED red 1 / orange 4 red ● → orange ●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 Y Diagnose[97] | LED red 1 / orange 1 red ● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 Y Diagnose[97] | LED red 1 / orange 2 red ● → orange ●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 Y Diagnose[97] | LED red 1 / orange 3 red ● → orange ●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 Y Diagnose[97] | LED red 1 / orange 4 red ● → orange ●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 Y Diagnose[97] | LED red 1 / orange 5 red ● → orange ●●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 YF Diagnose[98] | LED red 1 / orange 1 red ● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 YF Diagnose[98] | LED red 1 / orange 4 red ● → orange ●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 20 |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 62 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E80 |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | Signal lamp H1 (overtemperature) onMotor or discharge gas overtemperature has tripped (lamp wired per wiring diagram). (The manual does not give the colour.) Alarm symbol: red steady |
| Kriwan INT69 F Diagnose[94] | LED green 1 / orange 1Warning: motor winding temperature is above the permitted value; the motor still runs. Compressor symbol: green ● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 F Diagnose[94] | LED green 1 / orange 4Warning: open or short circuit on the motor temperature sensor input. Compressor symbol: green ● → orange ●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
The thermistor (PTC) in the motor windings reports too high a temperature, or its circuit to the drive is open.
Check: Measure the thermistor resistance and its wiring to the drive input; if the circuit is intact, look for why the motor runs hot (overload, poor cooling, low suction gas flow, phase fault).
Motor phase missing
| Controller | Code |
|---|---|
| Danfoss VLT FC 103[14] | A30 |
| Danfoss VLT FC 103[14] | A31 |
| Danfoss VLT FC 103[14] | A32 |
| Danfoss Optyma iCO2[46] | H27 |
| Danfoss CDS303/CDS803[69] | A30 |
| Danfoss CDS303/CDS803[69] | A31 |
| Danfoss CDS303/CDS803[69] | A32 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A3 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A30 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A31 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A32 |
| NIBE F1255 ground source heat pump[78] | 435 |
| NIBE F1255 ground source heat pump[78] | 447 |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | 12 flashes red ●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 18 |
| Temperzone UC8 unit controller[100] | F117 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E61 |
| ActronAir Aires and Advance 19–25 kW[137] | E61 |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | Fan LED red 4xPhase failure on the incoming supply. Fan symbol: red ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Kriwan INT69 UY Diagnose[96] | LED red 2 / orange 4Restart delay running after a phase-monitoring error; the unit stays off until it expires. Power lamp: red ●● → orange ●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Outdoor board LED1+LED2 blinkingReverse or open phase on the outdoor power terminal block (L1, L2, L3). (The manual does not give the colour.) Power lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| IVT Geo 500/600 series ground source heat pump[177] | 5900Phase lost to the compressor; check the fuses. |
| IVT Geo 500/600 series ground source heat pump[177] | 5981Compressor turning the wrong way, usually temporary (info); if it repeats, check the U-V-W order between inverter and compressor. |
| IVT Geo 500/600 series ground source heat pump[177] | 5983Compressor turning the wrong way (alarm); check the U-V-W order between inverter and compressor. |
| IVT Geo 500/600 series ground source heat pump[177] | 5989No phase between the inverter control and the compressor motor; check the fuses. |
The drive has lost one of the phases between its output and the motor, or no motor is connected.
Check: Switch off and check the motor cable, terminals and any contactor or service switch between the drive and the motor, and measure the motor windings.
Earth fault or short circuit at the motor output
| Controller | Code |
|---|---|
| Danfoss VLT FC 103[14] | A14 |
| Danfoss VLT FC 103[14] | A16 |
| Danfoss CDS303/CDS803[69] | A14 |
| Danfoss CDS303/CDS803[69] | A45 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A14 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A16 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A44 |
| Danfoss CDS303/CDS803[69] | A16 |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 4104 |
| Goodman DX20VC inverter condensing unit[105] | E31 |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | LED red 1 s red ● · 1 s on, 1 s off |
| Temperzone UC8 unit controller[100] | F125 |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | Fan LED red 6xPower module failure: short to earth or damaged motor winding. Fan symbol: red ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
Current leaks from the output phases to earth, or two phases are short-circuited, in the motor cable or in the motor itself.
Check: Switch off and isolate, then measure the insulation of the motor and the motor cable phase to earth and phase to phase; look for damaged cables, moisture in terminal boxes and burnt windings.
Compressor start failed
| Controller | Code |
|---|---|
| Danfoss VLT FC 103[14] | A18 |
| Carel Heos[18] | CSF |
| Danfoss Optyma iCO2[46] | H29 |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 14 |
| Carel µChiller[60] | A44 |
| Copeland Digital Compressor Controller[61] | 4 flashes red ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland PerformanceAlert diagnostic module[62] | 4 flashes yellow ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (scroll AC)[64] | LED yellow 4 yellow ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (scroll AC)[64] | LED red 4 red ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (UltraTech scroll)[66] | LED yellow 4 yellow ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (UltraTech scroll)[66] | LED red 4 red ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED yellow 4 yellow ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED red 4 red ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Danfoss CDS303/CDS803[69] | A18 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A18 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A99 |
| Danfoss VLT FC 103[14] | A99 |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | L9 |
| LG Multi V 5 VRF outdoor units[77] | CH26 |
| NIBE F1255 ground source heat pump[78] | 449 |
| Secop BD electronic units (BD35F/BD50F/BD35K/BD80CN, 101N0212/0340/0390/0420/0510/0650)[80] | 3 flashes red ●●● · 0.25 s on, 0.25 s off · pause 2.75 s |
| AHT electronic controller (plug-in cases, standard)[82] | FU3 |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | START |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | 8 flashes red ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | UF |
| Goodman DX20VC inverter condensing unit[105] | E36 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | H02 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | H02 |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | 1D |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A17 |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 16 |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 11 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E64 |
| ActronAir Aires and Advance 19–25 kW[137] | E90 |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red lit / yellow blink / green darkCompressor start failure (10 s without synchronous running). Alarm symbol: red ● → yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | Fan LED red 11xStart attempted while the fan was turning backwards. Fan symbol: red ●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D802 yellow (3 s on / 0.5 s off)Current error: Compressor lock (1D). Alarm symbol: yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp B 4 flashesUF compressor overcurrent with locked compressor (pattern B = outdoor/other unit: lamp on for about 3 s, then the flashes). Alarm symbol: green ●●●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault R-on Y-blinkCompressor start failure: not synchronised for 10 s (red on, yellow blink, green off). Alarm symbol: red ● → yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| IVT AirX air-to-water heat pump[175] | 5506The compressor did not start; often a temporary disturbance. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5506The compressor did not start; often a temporary disturbance. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5610Outdoor unit code 26; IVT gives no detail, on LG-built outdoor units this code usually means the compressor rotor position was not found at start. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5611Outdoor unit code 26; IVT gives no detail, on LG-built outdoor units this code usually means the compressor rotor position was not found at start. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5648Compressor start current too high, LG code 73 (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5649Compressor start current too high, LG code 73 (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5506The compressor does not start; switch the heat pump supply off and on. |
| IVT Geo 312/412 ground source heat pump[178] | 5506The compressor does not start; switch the heat pump supply off and on. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5506The compressor did not start within 2 min of the start signal; a new attempt is allowed after another 2 min. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 6209The compressor does not start. |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 5 + Timer 5The compressor does not follow the inverter (rotor position or start failure, code 1A): check that both service valves are open, winding resistance and compressor leads. red + green ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 5 + Timer 5Compressor rotor position or start fault (1A). green + orange ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 1ACompressor rotor position or start fault. |
| Fujitsu inverter outdoor unit PCB, models 9–30 (older, one red LED)[187] | LED red 12Compressor rotor position fault. red ●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 9–30 (older, one red LED)[187] | LED red 13Compressor start failure. red ●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 36–54 (older, one red LED)[188] | LED red 13Compressor rotor position fault. red ●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 36–54 (older, one red LED)[188] | LED red 14Compressor start failure. red ●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter multi outdoor unit AOY30 (older, LEDs A–D)[190] | LED A–D 13 flashesCompressor rotor position fault. red ●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 93Inverter compressor start-up error (E.93.1). Check the compressor wiring, inverter PCB and compressor. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.93.1Inverter compressor start-up error: overcurrent at start, retried 60 times in each of 2 sets (at least about 100 min before the code shows; retries only with an indoor unit calling). Check the inverter PCB–compressor wiring, the inverter PCB (IPM) and the compressor for lock or shorted windings. |
The compressor did not reach the required start speed within the allowed time, which often points to a blocked rotor or too high a pressure difference at start.
Check: Check the pressure difference across the compressor at start (equalisation, start unloading), liquid or oil in the cylinders, and that the compressor turns freely; check the start speed and start time settings.
Voltage or phase fault
| Controller | Code |
|---|---|
| Danfoss ERC 21X[1] | AA1 |
| Copeland EazyCool ZX (XCM25D)[5] | E26 |
| Copeland EazyCool ZX (XCM25D)[5] | E20 |
| Copeland EazyCool ZX (XCM25D)[5] | E22 |
| Carel μC2SE[8] | ELS |
| Danfoss VLT FC 103[14] | A4 |
| Danfoss VLT FC 103[14] | A36 |
| Carpigiani AES PSP[15] | AL15 |
| Carel EVD evolution / EVD evolution twin[16] | Wrong power supply mode |
| Carel EVD evolution / EVD evolution twin[16] | Battery discharged |
| Carel EVD ice / EVD mini[17] | E7 |
| Carel µRack[25] | EHS |
| Carel µRack[25] | ELS |
| Carel µRack[25] | EL1 |
| Copeland EXD-SH1/2[26] | PFA |
| Copeland Stream condensing units (Next Gen CoreSense)[27] | 5 flashes orange ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland EazyCool ZX (XCM25D)[5] | L20 |
| Copeland EazyCool ZX (XCM25D)[5] | L21 |
| Copeland EazyCool ZX (XCM25D)[5] | E27 |
| Copeland EazyCool ZX (XCM25D)[5] | E30 |
| Copeland Large ZX 22–30 HP[29] | E20 |
| Copeland Large ZX 22–30 HP[29] | L20 |
| Copeland Large ZX 22–30 HP[29] | L21 |
| Copeland Large ZX 22–30 HP[29] | E22 |
| Copeland Large ZX 22–30 HP[29] | E26 |
| Copeland Large ZX 22–30 HP[29] | E27 |
| Copeland Large ZX 22–30 HP[29] | E30 |
| Danfoss AK-PC 782A/782B[38] | External power loss |
| Danfoss EKE 1A/1B/1C/1D[43] | E123 |
| Danfoss EKE 100[44] | A05 |
| Danfoss ERC 21X[1] | A99 |
| Danfoss Optyma Plus Module B Plus (P02)[45] | Y2-R1 yellow ●● → red ● · 1 s on, 1 s off · 1 s between colours · pause 3 s (timing assumed, not stated in the manual) |
| Danfoss Optyma Plus Module B Plus (P02)[45] | Y2-R2 yellow ●● → red ●● · 1 s on, 1 s off · 1 s between colours · pause 3 s (timing assumed, not stated in the manual) |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 21 |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 22 |
| Carel µC2SE for process chiller[59] | ELS |
| Carel µC2SE for process chiller[59] | EHS |
| Copeland Digital Compressor Controller[61] | 9 flashes red ●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland PerformanceAlert diagnostic module[62] | 6 flashes yellow ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland PerformanceAlert diagnostic module[62] | 7 flashes yellow ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland PerformanceAlert diagnostic module[62] | 9 flashes yellow ●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland compressor electronics communications (20–40 ton scroll)[65] | LED red 6 red ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland compressor electronics communications (20–40 ton scroll)[65] | LED red 7 red ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland compressor electronics communications (20–40 ton scroll)[65] | LED red 9 red ●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (UltraTech scroll)[66] | LED yellow 9 yellow ●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Communications (13–15 ton scroll)[67] | LED red 6 red ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Communications (13–15 ton scroll)[67] | LED red 7 red ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Communications (13–15 ton scroll)[67] | LED red 9 red ●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED yellow 6 yellow ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED red 6 red ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED red 7 red ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED yellow 9 yellow ●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Danfoss CDS303/CDS803[69] | A36 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A4 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A36 |
| Danfoss Gas Sensor DGS[71] | Voltage Error |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | DP 0X Voltage |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | Power Failure |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | PHA |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | UeHigh |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | L_high |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED red 1 red ● · 0.25 s on, 0.25 s off · pause 3 s |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED orange 2 orange ●● · 0.25 s on, 0.25 s off · pause 3 s |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED orange 15 orange ●●●●●●●●●●●●●●● · 0.25 s on, 0.25 s off · pause 3 s |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | P1 |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | U1 |
| Danfoss DHP heat pumps (DHP-A/AL/C/H/L)[76] | ERR PHASE SEQ. |
| LG Multi V 5 VRF outdoor units[77] | CH25 |
| LG Multi V 5 VRF outdoor units[77] | CH50 |
| NIBE F1255 ground source heat pump[78] | 431 |
| NIBE F1255 ground source heat pump[78] | 433 |
| Secop BD electronic units (BD35F/BD50F/BD35K/BD80CN, 101N0212/0340/0390/0420/0510/0650)[80] | 1 flashes red ● · 0.25 s on, 0.25 s off · pause 3.75 s |
| Secop SLV controller 105N46xx[81] | A93 |
| Secop SLV controller 105N46xx[81] | A95 |
| AHT electronic controller (plug-in cases, standard)[82] | FU7 |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | E93 |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | E95 |
| Hussmann parallel rack / CO2 cascade (basic alarm package)[86] | Phase Loss |
| Hussmann transcritical CO2 rack (rack controller alarms)[87] | Phase Loss |
| RDM DMTouch / miniDM[91] | Power Fail |
| Kriwan INT69 PYF Diagnose[95] | LED red 2 / orange 1 red ●● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 PYF Diagnose[95] | LED red 2 / orange 2 red ●● → orange ●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 PYF Diagnose[95] | LED red 2 / orange 3 red ●● → orange ●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 UY Diagnose[96] | LED red 2 / orange 1 red ●● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 UY Diagnose[96] | LED red 2 / orange 2 red ●● → orange ●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 UY Diagnose[96] | LED red 2 / orange 3 red ●● → orange ●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 UY Diagnose[96] | LED red 2 / orange 5 red ●● → orange ●●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 UY Diagnose[96] | LED red 3 / orange 1 red ●●● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 Y Diagnose[97] | LED red 2 / orange 1 red ●● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 Y Diagnose[97] | LED red 2 / orange 2 red ●● → orange ●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 Y Diagnose[97] | LED red 3 / orange 1 red ●●● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 YF Diagnose[98] | LED red 2 / orange 1 red ●● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 YF Diagnose[98] | LED red 2 / orange 2 red ●● → orange ●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 YF Diagnose[98] | LED red 2 / orange 3 red ●● → orange ●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 YF Diagnose[98] | LED red 5 / orange 2 red ●●●●● → orange ●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Temperzone UC8 unit controller[100] | F30 |
| Temperzone UC7 unit controller[101] | F30 |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 4102 |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 4103 |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | U9 |
| Goodman DX20VC inverter condensing unit[105] | E38 |
| Goodman DX20VC inverter condensing unit[105] | E42 |
| Goodman DX20VC inverter condensing unit[105] | E43 |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | LED yellow rapid yellow flashing fast (10 Hz) |
| Evco EVK214[109] | PF |
| Evco EV3 CHILL / HPRU (chiller, heat pump)[111] | APH |
| Hitachi multi-split heat pump[113] | 05 |
| Hitachi multi-split heat pump[113] | 06 |
| Thermia Atella / Robust[114] | ERR PHASE SEQ. |
| Full Gauge MT-514E Faston[122] | AVoL |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | P05 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | L31 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | P05 |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A21 |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 2 |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 19 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E27 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E29 |
| ActronAir Aires and Advance 19–25 kW[137] | E27 |
| ActronAir Aires and Advance 19–25 kW[137] | E29 |
| ActronAir Aires and Advance 19–25 kW[137] | E65 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | PC 01 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | PC 10 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | PC 11 |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | uHi |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | uLi |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | uLo |
| Danfoss ETC (True cabinets)[142] | Ulo |
| Danfoss ETC (True cabinets)[142] | UHi |
| Danfoss EETa (True cabinets, LED blink codes)[143] | 1+2 flashes |
| Taylor 736 soft serve freezer[153] | PHASES |
| Taylor 736 soft serve freezer[153] | PHASES/N |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er10 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er11 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er16 |
| Taylor R200 fry dispenser[157] | DC Power Low |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | EHI |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | ELO |
| Copeland (CPC) E2 RX/BX/CX controller[163] | REFR Phase Loss |
| Copeland (CPC) E2 RX/BX/CX controller[163] | ISD Missing Phase Trip |
| Copeland (CPC) E2 RX/BX/CX controller[163] | ISD Supply Voltage Trip |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | S.281 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | F.818 |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | 4 flashes |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | 12 flashes |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | 13 flashes |
| Copeland Digital Compressor Controller[61] | All LEDs flashing together24 VAC supply is too low for operation. Power lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red blink / yellow blink / green darkDC bus voltage too low or too high. Alarm symbol: red ● → yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | Fan LED offNo voltage to the fan motor (or power module cooling down); check supply. Power lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | Fan LED red 12xLine voltage too low. Fan symbol: red ●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | Fan LED red 13xLine voltage too high. Fan symbol: red ●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Running lamp 3, timer offZero-crossing signal detection error (EH 02). (The manual does not give the colour.) Alarm symbol: green ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Running lamp 2 + timer flashingOver- or undervoltage protection (PC 01). (The manual does not give the colour.) Alarm symbol: green ●● → orange ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Heatcraft Beacon II[30] | Display 888Shown briefly at power-up; if it stays, the board supply is below about 18 V. Power lamp: red steady |
| Heatcraft Beacon II[30] | Display darkDisplay not lit: no 24 V at the control board; check supply, transformer and wiring. Power lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland PerformanceAlert diagnostic module[62] | LED red + yellow flashing togetherMiswiring: the module C and L terminals do not get 85-265 V AC, or the contactor coil is on terminal P. Power lamp: red ● → yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland PerformanceAlert diagnostic module[62] | LED green offThe module does not power up: no line voltage on C and L, or they are not connected. Power lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland PerformanceAlert diagnostic module[62] | LED green only when compressor runsL and Y are probably swapped: the module needs a constant supply from the line side of the contactor. Power lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | Controller POWER LED offThe condenser controller has no supply power. Power lamp: green ● · 1 s on, 1 s off |
| Taylor R280 fry dispenser[158] | DCV power indicator off, switch litNo DC control voltage although the power switch is on; reset DC breaker CB1. (The manual does not give the colour.) Power lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Bitzer VARIPACK FMY+/FMU+ .. FSW+ (frequency inverter)[58] | Symbol mains interruptedThe incoming mains voltage has been interrupted. (The manual does not give the colour.) Power lamp: white steady |
| Danfoss Gas Sensor DGS[71] | LED offNo power to the sensor; check supply and wiring. Power lamp: green steady |
| Copeland CoreSense Diagnostics (scroll AC)[64] | LED red + yellow flashing together24 V AC control-circuit voltage is too low; the module keeps resetting and stored alerts are cleared. Power lamp: red ● → yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Temperzone UC8 unit controller[100] | Power light offNo mains at the controller: check supply, control circuit breaker, wiring and the board fuse. (The manual does not give the colour.) Power lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp B 11 flashesU9/UH over/undervoltage, sync signal or current sensor error (pattern B = outdoor/other unit: lamp on for about 3 s, then the flashes). Alarm symbol: green ●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | Light block all offIndoor unit power is off, or wiring between the receiving unit and the indoor unit is faulty. (The manual does not give the colour.) Power lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault R-blink Y-blinkDC bus voltage too low or too high (red blink, yellow blink, green off). Alarm symbol: red ● → yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| IVT AirX air-to-water heat pump[175] | 5453No supply to the outdoor unit; check the fuses. It can appear briefly at start-up or after a power cut and then clears itself. |
| IVT AirX air-to-water heat pump[175] | 5347Supply voltage to the installer module below 170 V; it resets when above 190 V for 2 min. |
| IVT AirX air-to-water heat pump[175] | 5362Mains overvoltage: loose main fuses, an unstable grid or, in some cases, a solar PV system. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5273Phase monitoring: check the fuse in the indoor unit feeding the outdoor unit and the main fuses. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5347Supply voltage to the installer module below 170 V; it resets when above 190 V for 2 min. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5362Mains overvoltage: loose main fuses, an unstable grid or, in some cases, a solar PV system. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5453No supply to the outdoor unit; check the fuses. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5636Wrong phase sequence or a missing phase, LG code 54 (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5637Wrong phase sequence or a missing phase, LG code 54 (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5273Phase monitoring: a fuse for the heat pump has tripped. |
| IVT Geo 500/600 series ground source heat pump[177] | 5347Supply voltage too low; check the fuses. |
| IVT Geo 500/600 series ground source heat pump[177] | 5362Mains voltage too high; check the main fuses for poor contact. |
| IVT Geo 500/600 series ground source heat pump[177] | 5370Overvoltage; the compressor stops and the alarm must be reset before it may restart. |
| IVT Geo 500/600 series ground source heat pump[177] | 5453No supply to the heat pump; check the main fuses for tripping or poor contact. |
| IVT Geo 500/600 series ground source heat pump[177] | 5905Supply voltage to the inverter control below 180 V AC. |
| IVT Geo 500/600 series ground source heat pump[177] | 5920Supply voltage to circulation pump PC0 below 150 V. |
| IVT Geo 500/600 series ground source heat pump[177] | 5922Supply voltage to circulation pump PC0 too high. |
| IVT Geo 500/600 series ground source heat pump[177] | 5939Supply voltage to circulation pump PC0 too low (info). |
| IVT Geo 312/412 ground source heat pump[178] | 5347Supply voltage too low; check the fuses. |
| IVT Geo 312/412 ground source heat pump[178] | 5362Mains voltage too high; check the main fuses for poor contact. |
| IVT Geo 312/412 ground source heat pump[178] | 5453No supply to the heat pump; check the main fuses for tripping or poor contact. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5273Phase monitoring: check the fuse in the indoor unit feeding the outdoor unit and the main fuses. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5347Supply voltage to the installer module below 170 V; it resets when above 190 V for 2 min. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5362Mains overvoltage: loose main fuses, an unstable grid or, in some cases, a solar PV system. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5453No supply to the outdoor unit; check the fuses. |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 4 + Timer 4The indoor unit cannot detect the supply frequency after power-on and stops permanently; usually an indoor PCB fault. red + green ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 8 + Timer 2Active filter module (AFM) voltage fault, permanent stop (code 19): check the choke coil and connectors, then the AFM or PCB. red + green ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 8 + Timer 3Active filter module (AFM) output voltage fault (code 19), first occurrence: check the wiring and the choke coil. red + green ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 4 + Timer 4Indoor unit cannot detect 50/60 Hz supply frequency (08). green + orange ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 8 + Timer 2Active filter module fault, second time, unit stops (19). green + orange ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 8 + Timer 3Active filter module fault, first time. green + orange ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 22 flashesActive filter fault. red ●●●●●●●●●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 08Power supply connection or 50/60 Hz detection fault: check supply and wiring. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 19Active filter module (AFM) fault. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 2ASupply frequency cannot be detected. |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | E8:00Wrong or faulty power supply connection. |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation blinking + Timer 2Outdoor power connection fault. green + red ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation blinking + Timer 12Active filter module (AFM) fault. green + red ●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wall-mounted multi indoor units (older, UK; two-stage lamp code)[186] | Red 4 + Green blinking, test button: Red blinking + Green 4Indoor control fault group; after the test button: power source fault. red + green ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu non-inverter outdoor unit PCB (older, two red LEDs)[189] | LED 1 1 + LED 2 steadyPower source fault. red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red steady + Green long pulses (D, E, F)Power failure has been detected. red + green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red rapid + Green 2 short (F)Three-phase supply connected in the wrong phase order. red + green ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | 05Reverse phase sequence or a missing phase on the main supply: measure all three phases and check the rotation with a phase-sequence meter; swap two incoming supply wires at the main terminals, never wires inside the unit. |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | 93The main supply dropped out for less than 2 s: check the supply, loose terminals and contactor contacts. |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | 94The main supply was off for more than 2 s: check the supply, the main fuses and the main switch. |
| Fujitsu AIRSTAGE J-II VRF – wired and simple remote controllers UTY-RNK*, UTY-RSK*, UTY-RHK* (error code on the display)[197] | 31Indoor unit power frequency abnormal: the indoor PCB cannot read the mains frequency. Check about 230 V AC on indoor terminals 1–2 and for voltage dips or noise; if the supply is good, replace the indoor PCB. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 31Indoor unit power frequency abnormal. Check about 230 V AC on indoor terminals 1–2, then the indoor PCB. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 67Inverter PCB short power interruption detected (E.67.2). Check the supply for dips and loose terminals. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.67.2Inverter PCB short power interruption detected (momentary power failure); indoor units show nothing. Check the supply for dips, loose terminals and the filter PCB. |
| Fujitsu AIRSTAGE J-II VRF – signal amplifier UTY-VSGX (7-segment display)[201] | No displayPower supply error: the 7-segment display stays dark. Check the power cable, the terminal–power PCB and power PCB–main PCB connections and reset the supply; with rated voltage present, replace the amplifier. |
| Fujitsu AIRSTAGE J-II VRF – network convertor UTY-VGGX (group remote or single split connection)[202] | No displayPower supply error: the 7-segment display stays dark. Check the power cable and the PCB connectors and reset the supply; with rated voltage present (220 V on single split use), replace the convertor. |
| Fujitsu AIRSTAGE J-II VRF – external switch controller UTY-TEKX (LED)[203] | LED off, no operationPower supply error: no 12 V (±10 %) between the red and black terminals. Check the indoor unit, the connection cable and its connector on the controller PCB; with 12 V present, replace the controller. |
| Fujitsu AIRSTAGE J-II VRF – indoor units (Operation/Timer/Filter lamps)[199] | Operation 3 + Timer 1 + Filter flashing fastIndoor unit power frequency abnormal (code 31). Check about 230 V AC on indoor terminals 1–2. The Filter lamp flickers fast (0.1 s) as the error marker; Operation and Timer flash their counts in turn. (The manual does not give the colour.) green + orange + red ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
The controller has measured too low a voltage, a missing phase or imbalance between the phases. The alarm is a protection function for the compressor.
Check: Measure the supply voltage on all phases during start and operation. Check fuses, terminals and cables.
DC link overvoltage in the drive
| Controller | Code |
|---|---|
| Danfoss VLT FC 103[14] | A7 |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 1 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A7 |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | UzHigh |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED orange 13 orange ●●●●●●●●●●●●● · 0.25 s on, 0.25 s off · pause 3 s |
| Danfoss CDS303/CDS803[69] | A7 |
| AHT electronic controller (plug-in cases, standard)[82] | FU4 |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | LED red/yellow 1 s red + yellow ● · 1 s on, 1 s off |
| Temperzone UC8 unit controller[100] | F103 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E62 |
| ActronAir Aires and Advance 19–25 kW[137] | E62 |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er54 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er54 |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | 8 flashes |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | Fan LED red 8xDC link voltage above limit. Fan symbol: red ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 8 + Timer 4Too high DC voltage in the PFC circuit of the inverter PCB (code 25); usually a PCB fault. red + green ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 8 + Timer 4PFC circuit fault in the outdoor inverter. green + orange ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 25PFC circuit fault (too high DC voltage in the inverter). |
The voltage in the drive's DC link has risen above its limit, usually because the motor feeds energy back during fast deceleration or because the mains voltage is too high.
Check: Check the mains voltage, lengthen the deceleration ramp or turn on overvoltage control; on fans that windmill in the wind, check that the drive catches the spinning fan instead of braking it hard.
DC link undervoltage in the drive
| Controller | Code |
|---|---|
| Danfoss VLT FC 103[14] | A8 |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 2 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A8 |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | UzLow |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED red 13 red ●●●●●●●●●●●●● · 0.25 s on, 0.25 s off · pause 3 s |
| LG Multi V 5 VRF outdoor units[77] | CH23 |
| Danfoss CDS303/CDS803[69] | A8 |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 4220 |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | 13 flashes red ●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | LED red/yellow fast red + yellow flashing fast (2 Hz) |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E63 |
| ActronAir Aires and Advance 19–25 kW[137] | E63 |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er56 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er57 |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | 7 flashes |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red blink / yellow blink / green litCharging circuit fault: bus voltage below 100 V twice after start-up. Alarm symbol: red ● → yellow ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | Fan LED red 7xDC link voltage below limit. Fan symbol: red ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED orange 7Warning: DC link voltage is low. Fan symbol: orange ●●●●●●● · 0.25 s on, 0.25 s off · pause 3 s |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault R-blink Y-blink G-onCharging circuit fault: bus voltage below 100 V twice after start-up (red blink, yellow blink, green on). Alarm symbol: red ● → yellow ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5604Outdoor unit code 23; IVT gives no detail, on LG-built outdoor units this code usually means DC link voltage too low or too high. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5605Outdoor unit code 23; IVT gives no detail, on LG-built outdoor units this code usually means DC link voltage too low or too high. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.97.4Outdoor fan motor undervoltage: the DC supply has dropped to 180 V or less. Check the mains supply for dips and loose wiring, then the electrolytic capacitor and DC detection on the main PCB. |
The voltage in the drive's DC link has fallen below its limit, usually because the supply voltage dips or a phase or fuse is lost.
Check: Measure the mains voltage on all three phases under load, check fuses, contactors and terminals ahead of the drive, and check that the supply matches the drive's rated voltage.
Drive overheated or cooling fan fault
| Controller | Code |
|---|---|
| Danfoss VLT FC 103[14] | A29 |
| Danfoss VLT FC 103[14] | W24 |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 11 |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 12 |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 29 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | W24 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A69 |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | TFE |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | TE_high |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | TEI_high |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED red 3 red ●●● · 0.25 s on, 0.25 s off · pause 3 s |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED orange 4 orange ●●●● · 0.25 s on, 0.25 s off · pause 3 s |
| Danfoss VLT FC 103[14] | W23 |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | L4 |
| LG Multi V 5 VRF outdoor units[77] | CH62 |
| NIBE F1255 ground source heat pump[78] | 439 |
| Danfoss CDS303/CDS803[69] | A29 |
| Danfoss CDS303/CDS803[69] | A65 |
| Secop BD electronic units (BD35F/BD50F/BD35K/BD80CN, 101N0212/0340/0390/0420/0510/0650)[80] | 5 flashes red ●●●●● · 0.25 s on, 0.25 s off · pause 1.75 s |
| Secop SLV controller 105N46xx[81] | A92 |
| Secop SLV controller 105N46xx[81] | A97 |
| Secop SLV controller 105N46xx[81] | A98 |
| AHT electronic controller (plug-in cases, standard)[82] | FU5 |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | E75 |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | E92 |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 4230 |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 4260 |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | 4 flashes red ●●●● · 0.5 s on, 0.5 s off · pause 2.5 s |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | U5 |
| Goodman DX20VC inverter condensing unit[105] | E32 |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | LED red 1 s + fast red ● → red ● · 1 s on, 1 s off |
| Hitachi multi-split heat pump[113] | 54 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | P07 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | P07 |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A14 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E28 |
| ActronAir Aires and Advance 19–25 kW[137] | E28 |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er55 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er55 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | S.282 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | F.819 |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | 9 flashes |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | 17 flashes |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red lit / yellow blink / green litCompressor IPM overheat (above 96 °C). Alarm symbol: red ● → yellow ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | Fan LED red 9xPower module is cooling down. Fan symbol: red ●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED orange 6Warning: temperature inside the electronics is high. Fan symbol: orange ●●●●●● · 0.25 s on, 0.25 s off · pause 3 s |
| Bitzer VARIPACK FMY+/FMU+ .. FSW+ (frequency inverter)[58] | Symbol reduced switching frequencyThe inverter has lowered its switching frequency because the heat sink is hot. (The manual does not give the colour.) Symbol: white steady |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp B 7 flashesU5 heat-sink temperature abnormal (pattern B = outdoor/other unit: lamp on for about 3 s, then the flashes). Alarm symbol: green ●●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault R-on Y-blink G-onCompressor IPM overheating (above about 96 °C) (red on, yellow blink, green on). Alarm symbol: red ● → yellow ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| IVT AirX air-to-water heat pump[175] | 5302Inverter internal temperature above 80 °C (warning). |
| IVT AirX air-to-water heat pump[175] | 5303Inverter too hot (alarm). |
| IVT AirX air-to-water heat pump[175] | 5387The PFC (input) stage of the compressor inverter has overheated. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5302Inverter internal temperature above 80 °C (warning). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5303Inverter too hot (alarm). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5387The PFC (input) stage of the compressor inverter has overheated. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5642Inverter temperature above 85 °C, LG code 62 (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5643Inverter temperature above 85 °C, LG code 62 (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5302Compressor inverter too hot because of poor heat transfer to its cooling loop (warning). |
| IVT Geo 500/600 series ground source heat pump[177] | 5303Compressor inverter too hot because of poor heat transfer to its cooling loop (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5387The compressor inverter is too hot. |
| IVT Geo 312/412 ground source heat pump[178] | 5302Compressor inverter too hot because of poor heat transfer to its cooling loop (warning). |
| IVT Geo 312/412 ground source heat pump[178] | 5303Compressor inverter too hot because of poor heat transfer to its cooling loop (alarm). |
| IVT Geo 312/412 ground source heat pump[178] | 5387The compressor inverter is too hot. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5302Inverter internal temperature above 80 °C (warning). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5303Inverter too hot (alarm). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5387The PFC (input) stage of the compressor inverter has overheated. |
The drive's heatsink or electronics are too hot, or its cooling fan is not running, so the drive warns and then trips.
Check: Check the air temperature around the drive, that the cooling fans run and that the heatsink and air paths are clean and free; also check the load and the motor cable length.
Flow switch has tripped
| Controller | Code |
|---|---|
| Carel μC2SE[8] | FL |
| Danfoss AK-PC 781A[37] | Flow switch alarm |
| Carel µC2SE for process chiller[59] | FL |
| Carel µChiller[60] | A10 |
| Danfoss DHP heat pumps (DHP-A/AL/C/H/L)[76] | BRINEFLOW LOW |
| Evco EV3 HP / EVD HP (heat pump)[110] | AFLo |
| Evco EV3 CHILL / HPRU (chiller, heat pump)[111] | AFLo |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A01 |
| RDM Mercury AC and roof top unit controllers[130] | Evap. Press/Pump Fault |
| RDM Mercury AC and roof top unit controllers[130] | Evaporator Lock Alarm |
| RDM Mercury AC and roof top unit controllers[130] | Eloc |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | S.275 |
| BAC Nexus modular hybrid cooler (NXF controls)[172] | Al_FlowSwitch |
| IVT AirX air-to-water heat pump[175] | 5451Heating-water flow too low during defrost, so the outdoor coil cannot be defrosted safely. |
| IVT AirX air-to-water heat pump[175] | 5252Water flow between outdoor and indoor unit is restricted (detected by the heat pump, not a flow switch); check the filter. |
| IVT AirX air-to-water heat pump[175] | 5594Air in the heating system; vent it, open the thermostats and clean the filter. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5252Water flow between outdoor and indoor unit is restricted (detected by the heat pump, not a flow switch); check the filter. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5451Heating-water flow too low during defrost; heating water may also be too cold. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5594Air in the heating system; vent it, open the thermostats and clean the filter. |
| IVT Geo 500/600 series ground source heat pump[177] | 5252Heating-medium temperature difference above 13 K in heating or 7 K in cooling, meaning too little flow (closed thermostats, dirty return filter). |
| IVT Geo 500/600 series ground source heat pump[177] | 5563Brine temperature difference TB0-TB1 too large, meaning too little brine flow: clogged strainer or air in the collector (warning). |
| IVT Geo 500/600 series ground source heat pump[177] | 5565Brine temperature difference TB0-TB1 too large, meaning too little brine flow: clogged strainer or air in the collector (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5594Air in the system or a flow problem on the heating side. |
| IVT Geo 500/600 series ground source heat pump[177] | 5918Flow through circulation pump PC0 too low; check, vent and fill the heating system. |
| IVT Geo 312/412 ground source heat pump[178] | 5252Heating-medium temperature difference above 13 K in heating or 7 K in cooling, meaning too little flow (closed thermostats, dirty return filter). |
| IVT Geo 312/412 ground source heat pump[178] | 5563Brine temperature difference TB0-TB1 too large, meaning too little brine flow: clogged strainer or air in the collector (warning). |
| IVT Geo 312/412 ground source heat pump[178] | 5565Brine temperature difference TB0-TB1 too large, meaning too little brine flow: clogged strainer or air in the collector (alarm). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5252Water flow between outdoor and indoor unit is restricted (detected by the heat pump, not a flow switch); check the filter. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5451Heating-water flow too low during defrost; heating water may also be too cold. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5594Air in the heating system; vent it, open the thermostats and clean the filter. |
The flow switch on the water or brine side signals too little flow, and the unit stops so that the evaporator does not freeze.
Check: Check pump, strainer, valves and air in the circuit before resetting.
Water or brine pump fault
| Controller | Code |
|---|---|
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | S.277 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | F.788 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | F.820 |
| BAC Nexus modular hybrid cooler (NXF controls)[172] | Al_PumpmFault |
| BAC TrilliumSeries adiabatic cooler TRF[174] | 1 |
| BAC TrilliumSeries adiabatic cooler TRF[174] | 2 |
| BAC TrilliumSeries adiabatic cooler TRF[174] | 3 |
| BAC TrilliumSeries adiabatic cooler TRF[174] | 4 |
| IVT AirX air-to-water heat pump[175] | 5285Frost risk in the heating system because circulation pump PC0 has no supply voltage. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5285Frost risk in the heating system because circulation pump PC0 has no supply voltage. |
| IVT Geo 500/600 series ground source heat pump[177] | 5567Brine pump PB3 reports an internal fault; a clogged strainer or air in the brine can also cause it (warning). |
| IVT Geo 500/600 series ground source heat pump[177] | 5569Brine pump PB3 reports an internal fault; a clogged strainer or air in the brine can also cause it (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5917No communication with heating circuit pump PC0. |
| IVT Geo 500/600 series ground source heat pump[177] | 5919Circulation pump PC0 is blocked; check the particle filter and the water quality. |
| IVT Geo 500/600 series ground source heat pump[177] | 5921Internal fault in circulation pump PC0; switch its supply off and on. |
| IVT Geo 500/600 series ground source heat pump[177] | 5938The electronics of pump PC0 are too hot because the plant room is above 35 °C. |
| IVT Geo 312/412 ground source heat pump[178] | 5567Brine pump PB3 reports an internal fault; a clogged strainer or air in the brine can also cause it (warning). |
| IVT Geo 312/412 ground source heat pump[178] | 5569Brine pump PB3 reports an internal fault; a clogged strainer or air in the brine can also cause it (alarm). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5285Frost risk in the heating system because circulation pump PC0 has no supply voltage. |
The circulation or spray water pump does not run as commanded: its electronics report a fault, it draws no current, it does not answer the controller, or it has been locked out after repeated failures.
Check: Check supply and fuse to the pump, the signal cable, that the pump turns freely and is not running dry or air-locked, and that the valves on the water side are open.
Water or brine pressure too low
| Controller | Code |
|---|---|
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | M.32 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | F.022 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | Symbol filling pressure flashingHeating circuit filling pressure is outside the permitted range. (The manual does not give the colour.) Water symbol: white ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| IVT Geo 500/600 series ground source heat pump[177] | 5276Brine (collector) pressure too low. |
| IVT Geo 500/600 series ground source heat pump[177] | 5923Circulation pump PC0 runs dry: fill and vent the heating circuit and check the filter. |
| IVT Geo 500/600 series ground source heat pump[177] | 5940Air in circulation pump PC0: fill and vent the heating circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5994Low brine pressure. |
| IVT Geo 312/412 ground source heat pump[178] | 5276Brine (collector) pressure too low. |
The pressure in the heating, cooling or brine circuit has fallen below the minimum, usually from a leak, air in the system or a too small expansion vessel, so the unit stops to protect the pump and heat exchanger.
Check: Read the system pressure, top up and bleed the circuit, look for leaks and check the expansion vessel pre-charge and the pressure sensor.
Antifreeze alarm
| Controller | Code |
|---|---|
| Carel ir33[11] | AFr |
| Carel ir33+ VCC[20] | AFr |
| Carel SmartCella / SmartCella 3PH[24] | AFr |
| Danfoss EKE 1A/1B/1C/1D[43] | A994 |
| Danfoss EKE 100[44] | A30 |
| Carel µC2SE for process chiller[59] | A1 |
| Carel µChiller[60] | A28 |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | A5 |
| Danfoss DHP heat pumps (DHP-A/AL/C/H/L)[76] | BRINE OUT |
| LG Multi V 5 VRF outdoor units[77] | CH187 |
| NIBE F1255 ground source heat pump[78] | 60 |
| NIBE F1255 ground source heat pump[78] | 160 |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | LEAVING BRINE TEMPERATURE LOW |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | ENTERING BRINE TEMPERATURE LOW |
| Evco EV3 HP / EVD HP (heat pump)[110] | AFr1 |
| Evco EV3 CHILL / HPRU (chiller, heat pump)[111] | AFr |
| Evco EV3 MVC / EVD MVC (air handling)[112] | AL05 |
| Hitachi multi-split heat pump[113] | 13 |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A04 |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | AFr |
| Copeland (CPC) E2 RX/BX/CX controller[163] | A FreezeStat Input Is Too Low |
| Vaillant aroSTOR plus VWL B/BM 200/6, 260/6[171] | E09 |
| IVT AirX air-to-water heat pump[175] | 5375Freeze protection of the condenser (water side) has stopped the unit, usually because of poor circulation to the heat pump. |
| IVT AirX air-to-water heat pump[175] | 5374Frost risk in the condenser from poor water flow; check balancing valves, thermostats, filter, air and system pressure. |
| IVT AirX air-to-water heat pump[175] | 5444Frost protection active; check water circulation and that the outdoor fan is not blocked by snow, ice or objects, then run the outdoor unit test. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5374Frost risk in the condenser from poor water flow; check balancing valves, thermostats, filter, air and system pressure. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5375Frost risk in the condenser (alarm); check balancing valves, thermostats, filter, air and system pressure. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5444Frost protection active; check water circulation and that the outdoor fan is not blocked by snow, ice or objects, then run the outdoor unit test. |
| IVT Geo 500/600 series ground source heat pump[177] | 5285Freeze protection: T0, TC1 or TC0 has been below 5 °C for 10 min. |
| IVT Geo 500/600 series ground source heat pump[177] | 5374Condenser freeze protection warning: poor or no circulation in the heating system. |
| IVT Geo 500/600 series ground source heat pump[177] | 5375Condenser freeze protection alarm: poor or no circulation in the heating system. |
| IVT Geo 312/412 ground source heat pump[178] | 5285Freeze protection: T0, TC1 or TC0 has been below 5 °C for 10 min. |
| IVT Geo 312/412 ground source heat pump[178] | 5374Condenser freeze protection warning: poor or no circulation in the heating system. |
| IVT Geo 312/412 ground source heat pump[178] | 5375Condenser freeze protection alarm: poor or no circulation in the heating system. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5374Frost risk in the condenser from poor water flow; check balancing valves, thermostats, filter, air and system pressure. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5375Frost risk in the condenser (alarm); check balancing valves, thermostats, filter, air and system pressure. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5444Frost protection active; check water circulation and that the outdoor fan is not blocked by snow, ice or objects, then run the outdoor unit test. |
A probe set up as antifreeze probe has measured a temperature below the antifreeze limit, and the compressor is stopped until the alarm is reset by hand.
Check: Check flow and temperature on the evaporator side (water or brine flow, frosted coil, low load), and the probe and its limit setting, before resetting.
Liquid level
| Controller | Code |
|---|---|
| Carel pRack pR300[22] | ALB05 |
| Carel pRack pR300T (transcritical CO2)[23] | ALB05 |
| Carel µRack[25] | A09 |
| Dixell XC645D[48] | A5 |
| NIBE F1255 ground source heat pump[78] | 53 |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | CHILLER LIQUID LEVEL LOW |
| RDM Intuitive Superpack / Transcritical Superpack[132] | Lh 1–Lh 3 |
| RDM Intuitive Superpack / Transcritical Superpack[132] | LL 1–LL 3 |
| Taylor 736 soft serve freezer[153] | FLU.LEV. |
| BAC Nexus modular hybrid cooler (NXF controls)[172] | Al_WaterLowLvl |
| BAC Nexus modular hybrid cooler (NXF controls)[172] | Al_WaterHighLvl |
| BAC TrilliumSeries adiabatic cooler TRF[174] | 6 |
| BAC TrilliumSeries adiabatic cooler TRF[174] | 7 |
| BAC TrilliumSeries adiabatic cooler TRF[174] | 15 |
| BAC TrilliumSeries adiabatic cooler TRF[174] | 16 |
A liquid level in a separator or vessel is outside its limits.
Check: Check the level sensor against the sight glass, the level control valve and the charge.
Mix low or mix out
| Controller | Code |
|---|---|
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | MIX LOW FAILURE |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | MIX OUT FAILURE |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | ML |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | MO |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er00 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er00 |
| Taylor 736 soft serve freezer[153] | MIX LOW iconMix level in the hopper is low; refill soon. (The manual does not give the colour.) Water symbol: white steady |
| Taylor 736 soft serve freezer[153] | MIX OUT iconHopper almost empty; Auto is locked out and the freezer goes to Standby until mix is added. (The manual does not give the colour.) Water symbol: white steady |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | MIX-LOW light blinkingThe mix level in the hopper is running low; add mix. (The manual does not give the colour.) Water symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | MIX-LOW light steadyThe hopper is out of mix. (The manual does not give the colour.) Water symbol: red steady |
| Taylor R280 fry dispenser[158] | Display blinking oLow fry level warning: too little product in the hopper to reach the target weight. (The manual does not give the colour.) Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Taylor R280 fry dispenser[158] | Empty hopper light flashingThe hopper is empty or the target weight cannot be reached (also scale obstruction, calibration or bridged fries); the unselected basket LEDs flash too and dispensing stops. (The manual does not give the colour.) Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | Mix Low light onMix hopper is low; refill soon. (The manual does not give the colour.) Symbol: yellow steady |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | Mix Out light onHopper nearly empty; Auto is locked out and the freezer goes to Standby. (The manual does not give the colour.) Symbol: red steady |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | MIX LOW lamp flashingMix is low; portions may be small. Refill. (The manual does not give the colour.) Symbol: yellow ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carpigiani AES PSP[15] | Tank level LED 1/2 onMix in that tank is at minimum; about 10 portions left before the machine goes to storage. (The manual does not give the colour.) Symbol: red steady |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | Mix Low light onMix hopper is low; refill soon. (The manual does not give the colour.) Symbol: red steady |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | Mix Out light onMix hopper is almost empty; Auto is locked out and the freezer goes to Standby until mix is added and Auto pressed. (The manual does not give the colour.) Symbol: red steady |
The level sensor in the hopper reports too little mix (or none), so the machine stops freezing or will not run a heat treatment cycle.
Check: Refill the hopper; check the mix level probe, the feed tube and that the hopper is clean and correctly assembled.
Heat treatment cycle failed
| Controller | Code |
|---|---|
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | HEAT MODE FAILURE |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | COOL MODE FAILURE |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | TOTAL TIME FAILURE |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | POWER FAIL IN H/C |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | HT |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | CL |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | TT |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | PF |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er17 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er17 |
The heat treatment (pasteurising) cycle of a soft serve or shake freezer did not heat the mix high enough, cool it down again or finish within its time limits, for example after a power cut, a beater or pressure fault or too little mix, so the machine locks the product.
Check: Read the failure code and history in the service menu; check mix level, heaters, thermistors, refrigeration during the cool phase and the power supply, and handle the mix as the food safety rules require.
Water, CO2 or syrup supply low
| Controller | Code |
|---|---|
| Taylor frozen beverage freezers C300, C302, C303/C314, 345/346/349/355[149] | H2O PRESSURE LOW |
| Taylor frozen beverage freezers C300, C302, C303/C314, 345/346/349/355[149] | CO2 PRESSURE LOW |
| Taylor frozen beverage freezers C300, C302, C303/C314, 345/346/349/355[149] | SYRUP PRESS LOW |
| Taylor C392/C393/C394 frozen beverage freezers[150] | H2O Low |
| Taylor C392/C393/C394 frozen beverage freezers[150] | CO2 Low |
| Taylor C392/C393/C394 frozen beverage freezers[150] | Syrup Out |
| Taylor frozen beverage freezers C300, C302, C303/C314, 345/346/349/355[149] | Product light steadySyrup, water or CO2 is OUT for that barrel; refrigeration stops after the delay. (The manual does not give the colour.) Light symbol: white steady |
| Taylor R200 fry dispenser[157] | Display Hopper Empty flashingHopper empty: target weight not reached, dispensing stopped. (The manual does not give the colour.) Symbol: white ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
A frozen beverage machine has detected too low pressure in the incoming water, CO2 or syrup supply, so it stops or holds the freezing cylinders to protect the product and the cylinder.
Check: Check the water supply and pump, the CO2 bottle and regulator, syrup containers and lines, and the pressure switches.
Ice machine water system fault
| Controller | Code |
|---|---|
| True Ice TI/TCIM ice machines[147] | E24 |
| True Ice TI/TCIM ice machines[147] | E25 |
| True Ice TI/TCIM ice machines[147] | E27 |
| True Ice TI/TCIM ice machines[147] | E28 |
| True Ice TI/TCIM ice machines[147] | E29 |
| True Ice TI/TCIM ice machines[147] | H₂O |
The water side of an ice machine does not behave as expected: the sump fills or drains too slowly, water is lost, or the water pump does not move water, so the freeze and harvest cycle is stopped.
Check: Check water supply pressure and inlet filter, inlet and purge valves, the water level sensor and its tube, the pump and leaks around the sump and distributor.
Refrigerant pump differential pressure out of range
| Controller | Code |
|---|---|
| Hussmann pumped liquid CO2 secondary system (E2 rack controller alarms)[88] | LOW PUMP DIFFERENTIAL PRESSURE SHUT DOWN |
The pressure rise across the liquid pump of a pumped (secondary) CO2 or ammonia system has stayed too low or too high for longer than the delay, so the controller stops the pump and tries again after a pause; after repeated stops it locks out.
Check: Check the liquid level in the receiver or separator and the subcooling at the pump inlet (too little gives cavitation), that the suction strainer and valves are open, the pump rotation and the two pressure transmitters across the pump. A very high difference points to closed branch valves or a blocked supply line.
Refrigerant leak or gas detector alarm
| Controller | Code |
|---|---|
| Carel Heos[18] | LCA |
| Carel pRack pR300T (transcritical CO2)[23] | ALC51 |
| Carel pRack pR300T (transcritical CO2)[23] | ALC52 |
| Copeland EazyCool ZX (XCM25D)[5] | E48 |
| Copeland Large ZX 22–30 HP[29] | E47 |
| Copeland Large ZX 22–30 HP[29] | E48 |
| Danfoss AK-CC 550 / 550B[33] | AA2 |
| Danfoss AK-CC 550 / 550B[33] | AA3 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | AA2 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | AA3 |
| Danfoss AK-CC55 Water Loop[35] | AA3 |
| Danfoss EIM 365[40] | LOC Alarm |
| Danfoss Gas Sensor DGS[71] | LED red flashing red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss Gas Sensor DGS[71] | A! |
| Danfoss Gas Sensor DGS[71] | Overrange |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | A! |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | U0 |
| LG Multi V 5 VRF outdoor units[77] | CH230 |
| Heatcraft A2L Refrigerant Detection System (unit coolers)[79] | LED yellow/white flashing yellow ● → white ● · 0.5 s on, 0.5 s off · 0.5 s between colours (timing assumed, not stated in the manual) |
| Heatcraft A2L Refrigerant Detection System (unit coolers)[79] | LED red/white flashing red ● → white ● · 0.5 s on, 0.5 s off · 0.5 s between colours (timing assumed, not stated in the manual) |
| Hussmann parallel rack / CO2 cascade (basic alarm package)[86] | Refrigerant Loss |
| Hussmann transcritical CO2 rack (rack controller alarms)[87] | Rack Leak Detector |
| Hussmann pumped liquid CO2 secondary system (E2 rack controller alarms)[88] | CO2 LEAKAGE ALARM |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | P8 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | J30 |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | rSF |
| HTPG EcoNet enabled unit coolers[162] | A004 |
| Krack KR-A2L unit cooler (KE2 Evap leak sensor alarms)[164] | LEA |
| Krack KR-A2L unit cooler (KE2 Evap leak sensor alarms)[164] | Ln1 |
| Krack KR-A2L unit cooler (KE2 Evap leak sensor alarms)[164] | Ln2 |
| Krack KR-A2L unit cooler (KE2 Evap leak sensor alarms)[164] | LrE |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | Display CO2 flashingRefrigerant leak alarm (only when the refrigerant is set to CO2). (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss Gas Sensor DGS[71] | LED red slow flashingGas level above the warning threshold. Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss Gas Sensor DGS[71] | LED red fast flashingGas level above the critical threshold (buzzer on unless acknowledged). Alarm symbol: red flashing fast (2 Hz) |
| Danfoss Gas Sensor DGS[71] | Keypad LED red steadyGas alarm is active. Alarm symbol: red steady |
| Danfoss Gas Sensor DGS[71] | Display backlight redGas alarm is active (backlight changes from green to red). Alarm symbol: red steady |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | LED red steadyGas alarm is active; display backlight turns red. Alarm symbol: red steady |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp A 8 flashesP8 abnormal pipe temperature (wireless: count flashes after self-check; pattern A = indoor unit, starts after about 2.5 s off). Alarm symbol: green ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| Krack KR-A2L unit cooler (KE2 Evap leak sensor alarms)[164] | Danfoss sensor LED redRefrigerant at or above the alarm threshold; relay open, liquid solenoid closed, fans on. Alarm symbol: red steady |
| Krack KR-A2L unit cooler (KE2 Evap leak sensor alarms)[164] | Copeland sensor green blink 2 Hz + alarm 1 redLow refrigerant concentration detected (alarm 1, relay R1 open). Alarm symbol: green + red flashing fast |
| Krack KR-A2L unit cooler (KE2 Evap leak sensor alarms)[164] | Copeland sensor green blink 2 Hz + alarm 1 + alarm 2 redHigh concentration: mitigation running, compressors stopped and LLSV/discharge valves closed. Alarm symbol: green + red flashing fast |
| Krack KR-A2L unit cooler (KE2 Evap leak sensor alarms)[164] | Copeland sensor green steady + alarm 2 redGas gone but alarm 2 latched; R2 stays open until a manual reset (PM wire to ground for 1 s). Alarm symbol: green + red steady |
A gas detector or the controller has detected refrigerant in the air or a loss of refrigerant.
Check: Treat it as a real leak until proven otherwise: ventilate, measure with a hand-held detector, find and repair the leak, and check the detector.
Gas detector sensor fault
| Controller | Code |
|---|---|
| Danfoss Gas Sensor DGS[71] | LED yellow yellow steady |
| Danfoss Gas Sensor DGS[71] | Removed |
| Danfoss Gas Sensor DGS[71] | Out of Range |
| Danfoss Gas Sensor DGS[71] | Underrange |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | DP 0X Sensor Element |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | DP 0X Overrange |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | DP 0X Underrange |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | DP 0X Overtemp. |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | AP 0X Overrange |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | AP Underrange |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | J29 |
| Copeland (CPC) E2 RX/BX/CX controller[163] | IRLDS: Line/Filter Flow Fault |
| Copeland (CPC) E2 RX/BX/CX controller[163] | IRLDS: Self-Test Failure |
| Krack KR-A2L unit cooler (KE2 Evap leak sensor alarms)[164] | Li1 |
| Krack KR-A2L unit cooler (KE2 Evap leak sensor alarms)[164] | Li2 |
| Danfoss Gas Sensor DGS[71] | Keypad LED yellow steadyFault present; read the error list. Alarm symbol: yellow steady |
| Krack KR-A2L unit cooler (KE2 Evap leak sensor alarms)[164] | Copeland sensor alarm 2/fault red onlySensor malfunction detected (analogue output about 2.9 V / above 19 mA); manual reset needed. Alarm symbol: red steady |
The gas detector cannot measure reliably: the sensor head is missing, damaged, worn out or of the wrong type, or its signal is outside the range it should give, so a leak may go undetected.
Check: Check the cable and plug between sensor head and detector board, and that the gas type and range match the detector setup. Look for direct sun, heat or moisture at the sensor. Recalibrate or bump test with reference gas; if the fault returns, replace the sensor head. Until then, treat the room as unmonitored.
Refrigerant charge wrong
| Controller | Code |
|---|---|
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 1500 |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 1501 |
| Goodman DX20VC inverter condensing unit[105] | E41 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | P15 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | P15 |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A09 |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A26 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | EL 0C |
| ActronAir Nexus Touch Controller WTC-01[139] | EC |
| ActronAir UltraSlim 2 ducted split system[140] | EF |
| alpha innotec BWP 190S/260S DHW heat pump[168] | Er7 |
| alpha innotec BWP 190S/260S DHW heat pump[168] | Er9 |
| alpha innotec WWB 190 DHW heat pump[169] | E9 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Running lamp 8, timer offRefrigerant leak detected (EL 0C). (The manual does not give the colour.) Alarm symbol: green ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| IVT AirX air-to-water heat pump[175] | 5448Too little refrigerant in the circuit. |
| IVT AirX air-to-water heat pump[175] | 5527Too much refrigerant in the circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5448Too little refrigerant in the circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5527Too much refrigerant in the circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5448Too little refrigerant in the heat pump. |
| IVT Geo 500/600 series ground source heat pump[177] | 5527Too much refrigerant in the heat pump. |
| IVT Geo 500/600 series ground source heat pump[177] | 5984No or almost no refrigerant left in the circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5448Too little refrigerant in the heat pump. |
| IVT Geo 312/412 ground source heat pump[178] | 5527Too much refrigerant in the heat pump. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5448Too little refrigerant in the circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5527Too much refrigerant in the circuit. |
The unit compares its pressures, temperatures and valve positions and concludes that the system holds clearly too much or too little refrigerant, and limits or stops the compressor.
Check: Check subcooling and superheat against the manufacturer's charging chart, look for oil traces and leak test the joints if the charge is low. If it looks overcharged, check first for blocked condenser air flow, a closed service valve or non-condensables before removing refrigerant; weigh in the charge after any repair.
Leakage input outside its limit
| Controller | Code |
|---|---|
| Kriwan INT69 F Diagnose[94] | LED red 4 / orange 1 red ●●●● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 PYF Diagnose[95] | LED red 4 / orange 1 red ●●●● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 YF Diagnose[98] | LED red 4 / orange 1 red ●●●● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 YF Diagnose[98] | LED red 4 / orange 3 red ●●●● → orange ●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 F Diagnose[94] | LED green 4 / orange 1Warning: the leakage input is outside its permitted limit. Symbol: green ●●●● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 YF Diagnose[98] | LED green 4 / orange 1Warning: leakage input 1 is outside its permitted limit. Symbol: green ●●●● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 YF Diagnose[98] | LED green 4 / orange 3Warning: leakage input 2 is outside its permitted limit. Symbol: green ●●●● → orange ●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
The resistance measured between the leakage electrodes (or the leakage switch) of a protection relay is outside the set limits, which usually means liquid or dirt has reached the electrodes, or the electrode wiring is damaged.
Check: Look for liquid (water, oil, condensate) where the electrodes sit, dry and clean them, check the cable for damage or a short, and compare the limits set in the relay with the measured value.
Fan motor protection
| Controller | Code |
|---|---|
| Carel pRack pR300[22] | ALB07 |
| Carel pRack pR300[22] | ALF01 |
| Carel pRack pR300T (transcritical CO2)[23] | ALB07 |
| Carel µRack[25] | A22 |
| Carel µRack[25] | A26 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | A34 |
| Danfoss AK-PC 781A[37] | Fan Alarm x |
| Danfoss AK-PC 782A/782B[38] | Fan Alarm x |
| Danfoss Optyma iCO2[46] | A34 |
| Dixell XC645D[48] | InF |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | BLK |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | FB |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | TFM |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | TM_high |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | n_Limit |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | n_Low |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | Brake |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED red 6 red ●●●●●● · 0.25 s on, 0.25 s off · pause 3 s |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED red 8 red ●●●●●●●● · 0.25 s on, 0.25 s off · pause 3 s |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED red 9 red ●●●●●●●●● · 0.25 s on, 0.25 s off · pause 3 s |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED orange 5 orange ●●●●● · 0.25 s on, 0.25 s off · pause 3 s |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED orange 10 orange ●●●●●●●●●● · 0.25 s on, 0.25 s off · pause 3 s |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | E7 |
| LG Multi V 5 VRF outdoor units[77] | CH67 |
| Secop BD electronic units (BD35F/BD50F/BD35K/BD80CN, 101N0212/0340/0390/0420/0510/0650)[80] | 2 flashes red ●● · 0.25 s on, 0.25 s off · pause 3.25 s |
| AHT electronic controller (plug-in cases, standard)[82] | FU2 |
| Hussmann transcritical CO2 rack (rack controller alarms)[87] | Gas Cooler Fan Alarm |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | EF |
| Temperzone UC8 unit controller[100] | F10 |
| Temperzone UC8 unit controller[100] | F11 |
| Temperzone UC7 unit controller[101] | F10 |
| Temperzone UC7 unit controller[101] | F11 |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 4114 |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | 10 flashes red ●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | U8 |
| Goodman DX20VC inverter condensing unit[105] | E19 |
| Goodman DX20VC inverter condensing unit[105] | Eb0 |
| Goodman DX20VC inverter condensing unit[105] | Eb9 |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | VFD Alarm |
| Evco EV3 HP / EVD HP (heat pump)[110] | AtF1 |
| Evco EV3 CHILL / HPRU (chiller, heat pump)[111] | AF1 |
| Evco EV3 MVC / EVD MVC (air handling)[112] | AL09 |
| Evco EV3 MVC / EVD MVC (air handling)[112] | AL10 |
| Hitachi multi-split heat pump[113] | 09 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | P12 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | P22 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | P12 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | P22 |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | 1A |
| RDM Mercury AC and roof top unit controllers[130] | Fan 1 Fault |
| RDM Mercury AC and roof top unit controllers[130] | Fan 2 Fault |
| RDM Intuitive / Mercury pack and condenser controllers[131] | Cd |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E01 |
| ActronAir Aires and Advance 19–25 kW[137] | E1 |
| ActronAir Aires and Advance 19–25 kW[137] | E102 |
| ActronAir Aires and Advance 19–25 kW[137] | E103 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | EH 03 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | EC 07 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | EC 71 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | EC 72 |
| ActronAir Nexus Touch Controller WTC-01[139] | E3 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | S.260 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | F.718 |
| Vaillant aroSTOR plus VWL B/BM 200/6, 260/6[171] | E11 |
| BAC Nexus modular hybrid cooler (NXF controls)[172] | AL_FanCritical |
| BAC Nexus modular hybrid cooler (NXF controls)[172] | Al_MotBlocked_EBM_n |
| BAC Nexus modular hybrid cooler (NXF controls)[172] | Al_PhaseFault_EBM_n |
| BAC Nexus modular hybrid cooler (NXF controls)[172] | Al_MotSuperHeating_EBM_n |
| BAC Nexus modular hybrid cooler (NXF controls)[172] | Al_IntCircSuperHeat_EBM_n |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | 5 flashes |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | 3 flashes |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | 6 flashes |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | 11 flashes |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | 2 flashes |
| Carel µRack[25] | Icon fan + ALARM flashingFan alarm, e.g. fan thermal overload. (The manual does not give the colour.) Fan symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red blink / yellow lit / green litBuilt-in DC fan 1 speed below 60 rpm for 5 s. Alarm symbol: red ● → yellow ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red blink / yellow lit / green blinkBuilt-in DC fan 2 speed below 60 rpm for 5 s. Alarm symbol: red ● → yellow ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | Panel ALARM light (red) onOne or more EC fans have a fault; all fans run at emergency speed (about 40 %). Alarm symbol: red steady |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | Fan LED red 2xMotor temperature management is reducing maximum speed. Fan symbol: red ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | Fan LED red 3xHall sensor fault: rotor position not detected; reset power. Fan symbol: red ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | Fan LED red 5xMotor blocked; check the fan for obstruction. Fan symbol: red ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | Fan LED red 17xMotor overheated; fan stays off until temperature is normal. Fan symbol: red ●●●●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Running lamp 4, timer offIndoor fan speed outside the normal range (EH 03). (The manual does not give the colour.) Alarm symbol: green ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Running lamp 12, timer offOutdoor fan speed outside the normal range (EC 07). (The manual does not give the colour.) Alarm symbol: green ●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED orange 8Warning: braking mode, the fan has been driven backwards at high speed for a long time (e.g. by wind or another fan). Fan symbol: orange ●●●●●●●● · 0.25 s on, 0.25 s off · pause 3 s |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D801+D803 yellow (3 s on / 0.5 s off)Current error: Fan system error (1A). Alarm symbol: yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp B 8 flashesU8 outdoor fan protection stop (pattern B = outdoor/other unit: lamp on for about 3 s, then the flashes). Alarm symbol: green ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault R-blink Y-on G-onBuilt-in DC fan 1 below 60 rpm for 5 s (red blink, yellow on, green on). Fan symbol: red ● → yellow ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault R-blink Y-on G-blinkBuilt-in DC fan 2 below 60 rpm for 5 s (red blink, yellow on, green blink). Fan symbol: red ● → yellow ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5670Outdoor unit fan blocked, LG code 67 (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5671Outdoor unit fan blocked, LG code 67 (alarm). |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 5 + Timer 6Outdoor DC fan motor locked or abnormal current (code 1b): turn the fan by hand and check the motor supply from the PCB. red + green ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 6 + Timer 2Indoor fan still at 0 rpm about a minute after start (lock error, code 12): check the motor plug and turn the fan by hand. red + green ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 6 + Timer 3Indoor fan runs far below its target speed (speed error, code 12): check the motor, its plug and the fan wheel. red + green ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 5 + Timer 6Outdoor fan motor fault (1b). green + orange ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 6 + Timer 2Indoor fan motor locked (12). green + orange ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 6 + Timer 3Indoor fan motor speed abnormal (12). green + orange ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 15 flashesOutdoor fan motor fault. red ●●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 12Indoor fan motor locked or running at the wrong speed. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 1bOutdoor fan motor fault. |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | E:12Indoor fan failure: check fan and motor. |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation blinking + Timer 14Outdoor fan motor fault. green + red ●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation 6 + Timer blinkingIndoor fan failure. green + red ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wall-mounted multi indoor units (older, UK; two-stage lamp code)[186] | Red 6 + Green blinking, test button: Red blinking + Green 2Indoor fan fault group; after the test button: fan motor locked. red + green ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wall-mounted multi indoor units (older, UK; two-stage lamp code)[186] | Red 6 + Green blinking, test button: Red blinking + Green 3Indoor fan fault group; after the test button: fan speed wrong. red + green ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 36–54 (older, one red LED)[188] | LED red 15Upper outdoor fan motor fault. red ●●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 36–54 (older, one red LED)[188] | LED red 16Lower outdoor fan motor fault. red ●●●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter multi outdoor unit AOY30 (older, LEDs A–D)[190] | LED A–D 15 flashesUpper outdoor fan motor fault. red ●●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter multi outdoor unit AOY30 (older, LEDs A–D)[190] | LED A–D 16 flashesLower outdoor fan motor fault. red ●●●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red 6 short + Green rapid (B, E, F)Indoor fan failure. red + green ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | 19The overcurrent relay of the indoor (evaporator) fan motor has tripped: measure the motor current against the relay setting, check belt tension, bearings and duct pressure, then reset the relay by hand. |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | F1 57The internal thermostat of outdoor (condenser) fan motor 1 has opened (160 °C off, 130 °C on): check the motor current, bearings, rotation direction and the thermostat circuit. |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | F2 57The internal thermostat of outdoor (condenser) fan motor 2 has opened (160 °C off, 130 °C on): check the motor current, bearings, rotation direction and the thermostat circuit. |
| Fujitsu AIRSTAGE J-II VRF – wired and simple remote controllers UTY-RNK*, UTY-RSK*, UTY-RHK* (error code on the display)[197] | 51Indoor fan motor error: the fan stays at zero speed, or below about a third of the target, for 1 min. Turn the fan by hand, check the motor plug and windings (DC motor: Vm–GND below 300 kΩ means a shorted motor and PCB), then the PCB. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 51Indoor fan motor error (locked or too slow for 1 min). Check the fan, motor and PCB. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 97Outdoor fan motor 1 error: locked at start (E.97.1), DC undervoltage (E.97.4) or overheated (E.97.5). |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 98Outdoor fan motor 2 error: locked at start (E.98.1) or overheated (E.98.5). |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.97.1Outdoor fan motor 1 locked at start: 100 rpm or less 20 s after the start command, 15 times (the compressor stops after every third). Check for objects and that the fan turns by hand, the motor plug and windings, then the drive output on the main PCB (13.6–16.5 V DC). |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.97.5Outdoor fan motor 1 temperature abnormal: 220 rpm or less 60 s after the start command, 3 times within 3 h. Check for objects, a blocked coil, high ambient or recirculation, the static pressure setting, then the motor. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.98.1Outdoor fan motor 2 locked at start (same logic and checks as E.97.1). |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.98.5Outdoor fan motor 2 temperature abnormal (same logic and checks as E.97.5). |
| Fujitsu AIRSTAGE J-II VRF – indoor units (Operation/Timer/Filter lamps)[199] | Operation 5 + Timer 1 + Filter flashing fastIndoor fan motor error (code 51): locked or below a third of the target speed for 1 min. The Filter lamp flickers fast (0.1 s) as the error marker; Operation and Timer flash their counts in turn. (The manual does not give the colour.) green + orange + red ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
A condenser or evaporator fan motor protection or EC fan fault has tripped.
Check: Check the fan motor, its protection and supply, that the fan turns freely, and any fault code on the EC fan.
Electric auxiliary heater overheat protection
| Controller | Code |
|---|---|
| Danfoss DHP heat pumps (DHP-A/AL/C/H/L)[76] | AUX. HEATER |
| NIBE F1255 ground source heat pump[78] | 52 |
| Evco EV3 CHILL / HPRU (chiller, heat pump)[111] | ArEb |
| Evco EV3 MVC / EVD MVC (air handling)[112] | AL06 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | S.351 |
| IVT AirX air-to-water heat pump[175] | 5246Either the heating system pressure has dropped below 0.5 bar or the overheat protector of the electric heater has tripped; check the pressure first, then reset the protector. |
| IVT AirX air-to-water heat pump[175] | 5269Electric heater EE too hot, usually from poor water circulation or a dirty filter in the return line. |
| IVT AirX air-to-water heat pump[175] | 5272External auxiliary heater EM reports not ready, often because low pressure, air or poor circulation has tripped its protection. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5246Either the heating system pressure has dropped below 0.5 bar or the overheat protector of the electric heater has tripped; check the pressure first, then reset the protector. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5269Electric heater EE too hot, usually from poor water circulation or a dirty filter in the return line. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5272External auxiliary heater EM reports not ready, often because low pressure, air or poor circulation has tripped its protection. |
| IVT Geo 500/600 series ground source heat pump[177] | 5246Either the heating system pressure has dropped below 0.5 bar or the overheat protector of the electric heater has tripped; check the pressure first, then reset the protector. |
| IVT Geo 500/600 series ground source heat pump[177] | 5269Electric heater cassette EE too hot, usually from poor circulation or a dirty filter in the return line. |
| IVT Geo 500/600 series ground source heat pump[177] | 5272External auxiliary heater EM not working: system pressure below 0.5 bar or its overheat protector has tripped. |
| IVT Geo 312/412 ground source heat pump[178] | 5246Either the heating system pressure has dropped below 0.5 bar or the overheat protector of the electric heater has tripped; check the pressure first, then reset the protector. |
| IVT Geo 312/412 ground source heat pump[178] | 5269Electric heater cassette EE too hot, usually from poor circulation or a dirty filter in the return line. |
| IVT Geo 312/412 ground source heat pump[178] | 5272External auxiliary heater EM not working: system pressure below 0.5 bar or its overheat protector has tripped. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5246Either the heating system pressure has dropped below 0.5 bar or the overheat protector of the electric heater has tripped; check the pressure first, then reset the protector. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5269Electric heater EE too hot, usually from poor water circulation or a dirty filter in the return line. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5272External auxiliary heater EM reports not ready, often because low pressure, air or poor circulation has tripped its protection. |
The overheat protector (temperature limiter) on the electric immersion or flow heater has tripped, so the auxiliary heat is blocked until it is reset by hand.
Check: Check that water flows through the heater (pump running, valves open, system bled, strainer clean) before resetting the limiter. If it trips again or cannot be reset, check the limiter, its contactor and the heater element.
Control stopped
| Controller | Code |
|---|---|
| Danfoss EKC 202A/B/C[2] | A45 |
| Danfoss AK-CC 550A[3] | A45 |
| Danfoss Optyma Plus[4] | A45 |
| Danfoss AK-CC 450[32] | A45 |
| Danfoss AK-CC 550 / 550B[33] | A45 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | A45 |
| Danfoss AK-CC55 Water Loop[35] | A45 |
| Danfoss AK-CC 750[36] | Control stopped, MainSwitch=OFF |
| Danfoss AK-PC 781A[37] | Control stopped, MainSwitch=OFF |
| Danfoss AK-PC 782A/782B[38] | Control stopped, MainSwitch=OFF |
| Danfoss EKC 202D1[41] | A45 |
| Danfoss EKC 326A[42] | A45 |
| Danfoss EKE 1A/1B/1C/1D[43] | W002 |
| Danfoss EKE 100[44] | A00 |
| Danfoss ERC 21X[1] | A45 |
| Danfoss Optyma iCO2[46] | A45 |
| RDM Mercury 3 Twin Coil[92] | CASE OFF |
| Copeland Electronic Unit Controller[116] | POF |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | CASE OFF |
| RDM Intuitive / Mercury pack and condenser controllers[131] | Stby |
| Temperzone UC6 unit controller[135] | C |
| Temperzone UC6 unit controller[135] | d |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | 1 flashes |
| Temperzone UC7 unit controller[101] | Display flashing dashRemote On/Off input is open; unit is held off until the input is closed to G. (The manual does not give the colour.) Power lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | Fan LED red 1xRun enable missing; add enable signal or jumper. Fan symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| AHT electronic controller (plug-in cases, standard)[82] | Display ---Cooling has been switched off with the STANDBY button. (The manual does not give the colour.) Power lamp: red steady |
| Danfoss Optyma iCO2[46] | Display S10Stopped by the main switch (r12 or external input DI2). Power lamp: green steady |
| Full Gauge MT-512E 2HP[120] | LED control functions OFF steadyControl functions are switched off; the unit only indicates temperature (display may go dark with only this LED lit). (The manual does not give the colour.) Power lamp: red steady |
The controller is in standby: the main switch in the controller (parameter r12) is off, or a digital input stops it.
Check: Check parameter r12 and the digital inputs before troubleshooting further.
External alarm via digital input
| Controller | Code |
|---|---|
| Danfoss Optyma Plus[4] | A16 |
| Danfoss Optyma Plus[4] | A97 |
| Carel MPX[6] | IA |
| Carel MasterCella[7] | IA |
| Dixell XW270L/XW271L[9] | EAL |
| Zanotti GM/GS[10] | EA |
| Carel ir33[11] | IA |
| Carel ir33[11] | dA |
| Dixell XR60CX[12] | EA |
| Dixell XR60CX[12] | CA |
| Eliwell ID 974[13] | EA |
| Danfoss VLT FC 103[14] | W60 |
| Danfoss VLT FC 103[14] | A68 |
| Carel Heos[18] | IA |
| Carel Heos[18] | dA |
| Carel ir33 universale[19] | E03 |
| Carel ir33 universale[19] | E17 |
| Carel ir33 universale[19] | E18 |
| Carel ir33 universale[19] | Ed1 |
| Carel ir33 universale[19] | Ed2 |
| Carel ir33+ VCC[20] | IA |
| Carel ir33+ VCC[20] | dA |
| Carel MPXone[21] | IA |
| Carel MPXone[21] | dA |
| Carel SmartCella / SmartCella 3PH[24] | IA |
| Carel SmartCella / SmartCella 3PH[24] | dA |
| Danfoss AK-CC 450[32] | A15 |
| Danfoss AK-CC 450[32] | A16 |
| Danfoss AK-CC 550 / 550B[33] | A15 |
| Danfoss AK-CC 550 / 550B[33] | A16 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | A15 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | A16 |
| Danfoss AK-CC55 Water Loop[35] | A15 |
| Danfoss AK-CC55 Water Loop[35] | A16 |
| Danfoss AK-CC55 Water Loop[35] | A93 |
| Danfoss Optyma control AK-RC 113[39] | E8 |
| Danfoss EKC 202D1[41] | A15 |
| Danfoss EKC 202D1[41] | A16 |
| Danfoss EKC 202A/B/C[2] | A15 |
| Danfoss ERC 21X[1] | A15 |
| Danfoss AK-RC 251[47] | AE |
| Danfoss AK-RC 251[47] | AES |
| Dixell XC645D[48] | EA |
| Dixell XM669K/XM679K[50] | EA |
| Dixell XM669K/XM679K[50] | CA |
| Dixell XR06CX[51] | EA |
| Dixell XR06CX[51] | CA |
| Dixell XR35CX[52] | EA |
| Dixell XR35CX[52] | CA |
| Dixell XR460C[53] | EAL |
| Dixell XR460C[53] | bAL |
| Dixell XR70CX[54] | EA |
| Dixell XR70CX[54] | CA |
| Dixell XW60K/XW60L[55] | EA |
| Dixell XW60K/XW60L[55] | CA |
| Dixell XWi70K[56] | EA |
| Dixell XWi70K[56] | CA |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 27 |
| Bitzer VARIPACK FMY+/FMU+ .. FSW+ (frequency inverter)[58] | STO-F |
| Carel µC2SE for process chiller[59] | Ad1 |
| Carel µChiller[60] | A03 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A60 |
| Secop SLV controller 105N46xx[81] | A15 |
| Pego ECP200 EXPERT PULSE[89] | E8 |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | E8 |
| RDM DMTouch / miniDM[91] | Plant Fault |
| RDM Mercury 3 Twin Coil[92] | TrAP |
| RDM Mercury 3 Twin Coil[92] | Plt 1 |
| RDM Mercury 3 Twin Coil[92] | Plt 2 |
| RDM Mercury 3 Twin Coil[92] | Plt 3 |
| RDM Mercury 3 Twin Coil[92] | Plt 4 |
| Kriwan INT69 PYF Diagnose[95] | LED red 4 / orange 3 red ●●●● → orange ●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 PYF Diagnose[95] | LED red 5 / orange 3 red ●●●●● → orange ●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | EMERGENCY STOP |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | INTERLOCK |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | PA |
| Evco EV3203[107] | iA |
| Evco EV3 300 series[108] | iA |
| Evco EVK214[109] | iSd |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | ALrE |
| Full Gauge TC-900E Log[118] | ALrE |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | L30 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | L30 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | TrAP |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Man TrAP |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Plt1 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Plt2 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Plt3 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Plt4 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | PLnt |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | PLt1–PLt6 |
| RDM Intuitive / Mercury pack and condenser controllers[131] | gn |
| RDM Intuitive / Mercury pack and condenser controllers[131] | gEn 1–gEn 5 |
| RDM Intuitive / Mercury pack and condenser controllers[131] | Stage 1 LED flashing |
| RDM Intuitive / Mercury pack and condenser controllers[131] | Stage 2 LED flashing |
| RDM Intuitive / Mercury pack and condenser controllers[131] | Stage 3 LED flashing |
| RDM Intuitive Superpack / Transcritical Superpack[132] | gn 1–gn 16 |
| RDM Intuitive Superpack / Transcritical Superpack[132] | PLt 1–PLt 16 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | EH 0E |
| ActronAir Nexus Touch Controller WTC-01[139] | EE |
| ActronAir UltraSlim 2 ducted split system[140] | EE |
| Dixell XR/XW (True cabinets)[145] | EAL |
| Dixell XR/XW (True cabinets)[145] | BAL |
| Dixell XR03CX/XR04CX (Hillphoenix display cases)[159] | EA |
| Dixell XR03CX/XR04CX (Hillphoenix display cases)[159] | CA |
| Carel MPXzero (Hillphoenix display cases)[160] | IA |
| Carel MPXzero (Hillphoenix display cases)[160] | dA |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | IA |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | dA |
| Pego 202BASE electronic board[167] | E8 |
| BAC TrilliumSeries adiabatic cooler TRF[174] | 14 |
| LAE BR1-27/BR1-28/BR5-A/BR5-B/BD1-28/CD25[165] | ALr |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red blink / yellow lit / green darkSTO (safe torque off) interface disconnected. Alarm symbol: red ● → yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Carel ir33[11] | Icon alarm steadyDelayed external alarm input is active but its delay (A7) has not yet run out. (The manual does not give the colour.) Alarm symbol: red steady |
| Carel SmartCella / SmartCella 3PH[24] | Alarm icon steadyDelayed alarm from a digital input is active. (The manual does not give the colour.) Alarm symbol: red steady |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault R-blink Y-onSTO (safe torque off) interface disconnected after start-up (red blink, yellow on, green off). Alarm symbol: red ● → yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu AIRSTAGE J-II VRF – external switch controller UTY-TEKX (LED)[203] | LED on, SW1/SW2 no effectUTY-TEKX: switch input not detected. Check cable, DIP switches and the external switch (open >50 kΩ, closed <1 kΩ). (The manual does not give the colour.) green steady |
| Carel MasterCella[7] | Alarm icon steadyDelayed external digital-input alarm is pending, before its delay A7 runs out. (The manual does not give the colour.) Alarm symbol: red steady |
| Carel ir33+ VCC[20] | Alarm icon steadyA delayed alarm from a digital input is active. (The manual does not give the colour.) Alarm symbol: red steady |
A digital input (for example a safety chain, a pressure switch or an alarm from other equipment) has been activated. Some alarms stop the control.
Check: Find out what is connected to the input and fix the cause. Check the input setting in the controller.
Air sensor fault
| Controller | Code |
|---|---|
| Danfoss ERC 21X[1] | E29 |
| Danfoss EKC 202A/B/C[2] | E29 |
| Carel MPX[6] | rE |
| Carel MPX[6] | E0 |
| Carel MasterCella[7] | E0 |
| Dixell XW270L/XW271L[9] | P1 |
| Zanotti GM/GS[10] | E1 |
| Carel ir33[11] | rE |
| Carel ir33[11] | E0 |
| Dixell XR60CX[12] | P1 |
| Eliwell ID 974[13] | E1 |
| Carel Heos[18] | rE |
| Carel ir33 universale[19] | E01 |
| Carel ir33+ VCC[20] | rE |
| Carel ir33+ VCC[20] | E0 |
| Carel MPXone[21] | rE |
| Carel SmartCella / SmartCella 3PH[24] | rE |
| Carel SmartCella / SmartCella 3PH[24] | E0 |
| Heatcraft Beacon II[30] | E1 |
| Heatcraft Beacon II[30] | BXSEN |
| Danfoss AK-CC 450[32] | E25 |
| Danfoss AK-CC 450[32] | E26 |
| Danfoss AK-CC 450[32] | E34 |
| Danfoss AK-CC 550 / 550B[33] | E25 |
| Danfoss AK-CC 550 / 550B[33] | E26 |
| Danfoss AK-CC 550 / 550B[33] | E34 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | E25 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | E26 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | E34 |
| Danfoss AK-CC55 Water Loop[35] | E25 |
| Danfoss AK-CC55 Water Loop[35] | E26 |
| Danfoss AK-CC 750[36] | S3A sensor error |
| Danfoss AK-CC 750[36] | S4A sensor error |
| Danfoss Optyma control AK-RC 113[39] | E0 |
| Danfoss EKC 202D1[41] | E25 |
| Danfoss EKC 202D1[41] | E26 |
| Danfoss AK-RC 251[47] | E1 |
| Dixell XM669K/XM679K[50] | P1 |
| Dixell XR06CX[51] | P1 |
| Dixell XR35CX[52] | P1 |
| Dixell XR460C[53] | P1 |
| Dixell XR460C[53] | P2 |
| Dixell XR70CX[54] | P1 |
| Dixell XW60K/XW60L[55] | P1 |
| Dixell XWi70K[56] | P1 |
| Danfoss DHP heat pumps (DHP-A/AL/C/H/L)[76] | OUTDOOR SENSOR |
| LG Multi V 5 VRF outdoor units[77] | CH44 |
| Secop BD electronic units (BD35F/BD50F/BD35K/BD80CN, 101N0212/0340/0390/0420/0510/0650)[80] | 6 flashes red ●●●●●● · 0.25 s on, 0.25 s off · pause 1.25 s |
| Secop SLV controller 105N46xx[81] | E25 |
| Secop SLV controller 105N46xx[81] | E26 |
| AHT electronic controller (plug-in cases, standard)[82] | F1 |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | F1 |
| AHT GD-Cooler (GD-XLS, GD-XL)[84] | P1 |
| AHT plug-in cases with Danfoss controller (Paris, Ibiza, Malta, Manhattan)[85] | E01 |
| AHT plug-in cases with Danfoss controller (Paris, Ibiza, Malta, Manhattan)[85] | E02 |
| Pego ECP200 EXPERT PULSE[89] | E0 |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | E0 |
| RDM Mercury 3 Twin Coil[92] | Prb1 Ft |
| RDM Mercury 3 Twin Coil[92] | Prb2 Ft |
| Störk-Tronic ST121 / ST501 / ST551[93] | E1L |
| Störk-Tronic ST121 / ST501 / ST551[93] | E1H |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | P1 |
| Evco EV3203[107] | Pr1 |
| Evco EV3 300 series[108] | Pr1 |
| Evco EVK214[109] | Pr1 |
| Hitachi multi-split heat pump[113] | 11 |
| Thermia Atella / Robust[114] | ROOM SENSOR |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | Err1 |
| Full Gauge TC-900E Log[118] | Err1 |
| Full Gauge TC-940R[119] | Er1 |
| Full Gauge MT-512E 2HP[120] | Er1 |
| Full Gauge MT-512E Log[121] | Err1 |
| Full Gauge MT-514E Faston[122] | Err1 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | F10 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Prb1 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Prb2 |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | Prb |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | Prb 1–Prb 5 |
| RDM Mercury AC and roof top unit controllers[130] | Probe 1 |
| RDM Mercury AC and roof top unit controllers[130] | Probe 2 |
| RDM Mercury AC and roof top unit controllers[130] | Prb Flt |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E03 |
| ActronAir Aires and Advance 19–25 kW[137] | E3 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | EH 60 |
| ActronAir Nexus Touch Controller WTC-01[139] | E4 |
| ActronAir UltraSlim 2 ducted split system[140] | E2 |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | E01 |
| Danfoss ETC (True cabinets)[142] | E1 |
| Danfoss EETa (True cabinets, LED blink codes)[143] | 2+1 flashes |
| Carel PQ (True cabinets)[144] | E0 |
| Dixell XR/XW (True cabinets)[145] | P1 |
| LAE AR2/BR1/BIT25 and BR+/CD25/TM (True cabinets)[146] | E1 |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | E1 |
| Taylor R160 frozen food dispenser[156] | P1 |
| Taylor R200 fry dispenser[157] | Error 8 |
| Taylor R280 fry dispenser[158] | Err 8 |
| Dixell XR03CX/XR04CX (Hillphoenix display cases)[159] | P1 |
| Carel MPXzero (Hillphoenix display cases)[160] | rE |
| Carel MPXzero (Hillphoenix display cases)[160] | E1 |
| Carel MPXzero (Hillphoenix display cases)[160] | E3 |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | rE |
| HTPG EcoNet enabled unit coolers[162] | A103 |
| LAE AT1-5/AT2-5[166] | E1 |
| Pego 202BASE electronic board[167] | E0 |
| alpha innotec BWP 190S/260S DHW heat pump[168] | Er1 |
| Vaillant aroSTOR plus VWL B/BM 200/6, 260/6[171] | P04 |
| LAE BR1-27/BR1-28/BR5-A/BR5-B/BD1-28/CD25[165] | E1 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Running lamp 6, timer offIndoor sensor T1 (EH 60) or T2 (EH 61) open or short circuit. (The manual does not give the colour.) Alarm symbol: green ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | Display ErrThe temperature cannot be shown because of a sensor fault. (The manual does not give the colour.) Symbol: red steady |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp A 1 flashP1 intake (room) sensor error (wireless: count flashes after self-check; pattern A = indoor unit, starts after about 2.5 s off). Alarm symbol: green ● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| IVT AirX air-to-water heat pump[175] | 1037Outdoor sensor faulty or its cable broken; the unit heats on a fallback value meanwhile. |
| IVT AirX air-to-water heat pump[175] | 3091Thermistor in the room unit for heating circuit 1 is faulty while the bus works; a wrongly configured external room sensor gives the same code. |
| IVT AirX air-to-water heat pump[175] | 3092Thermistor in the room unit for heating circuit 2 is faulty while the bus works; a wrongly configured external room sensor gives the same code. |
| IVT AirX air-to-water heat pump[175] | 3093Thermistor in the room unit for heating circuit 3 is faulty while the bus works; a wrongly configured external room sensor gives the same code. |
| IVT AirX air-to-water heat pump[175] | 3094Thermistor in the room unit for heating circuit 4 is faulty while the bus works; a wrongly configured external room sensor gives the same code. |
| IVT AirX air-to-water heat pump[175] | 5201Outdoor sensor T1: open circuit in sensor or cable. |
| IVT AirX air-to-water heat pump[175] | 5202Outdoor sensor T1: short circuit in sensor or cable. |
| IVT AirX air-to-water heat pump[175] | 5203Outdoor sensor T1 faulty (alarm stage). |
| IVT AirX air-to-water heat pump[175] | 5408Air inlet sensor TL2: open circuit. |
| IVT AirX air-to-water heat pump[175] | 5409Air inlet sensor TL2: short circuit. |
| IVT AirX air-to-water heat pump[175] | 5410Air inlet sensor TL2 faulty (alarm stage). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 1037Outdoor sensor faulty or its cable broken; the unit heats on a fallback value meanwhile. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3091Thermistor in the room unit for heating circuit 1 is faulty while the bus works; a wrongly configured external room sensor gives the same code. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3092Thermistor in the room unit for heating circuit 2 is faulty while the bus works; a wrongly configured external room sensor gives the same code. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3093Thermistor in the room unit for heating circuit 3 is faulty while the bus works; a wrongly configured external room sensor gives the same code. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3094Thermistor in the room unit for heating circuit 4 is faulty while the bus works; a wrongly configured external room sensor gives the same code. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5201Outdoor sensor T1: open circuit in sensor or cable. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5202Outdoor sensor T1: short circuit in sensor or cable. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5203Outdoor sensor T1 faulty (alarm stage). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5395Air inlet sensor TL2: open circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5408Air inlet sensor TL2: open circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5409Air inlet sensor TL2: short circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5410Air inlet sensor TL2 faulty (alarm stage). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5624Outdoor unit air temperature sensor TL2 fault, LG code 44 (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5625Outdoor unit air temperature sensor TL2 fault, LG code 44 (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 3091Thermistor in the room unit (RC100/CR10) for heating circuit 1 is faulty while the bus works. |
| IVT Geo 500/600 series ground source heat pump[177] | 3092Thermistor in the room unit (RC100/CR10) for heating circuit 2 is faulty while the bus works. |
| IVT Geo 500/600 series ground source heat pump[177] | 3093Thermistor in the room unit (RC100/CR10) for heating circuit 3 is faulty while the bus works. |
| IVT Geo 500/600 series ground source heat pump[177] | 3094Thermistor in the room unit (RC100/CR10) for heating circuit 4 is faulty while the bus works. |
| IVT Geo 500/600 series ground source heat pump[177] | 3171Low battery in the wireless room sensor for heating circuit 1; replace the battery. |
| IVT Geo 500/600 series ground source heat pump[177] | 5201Outdoor sensor T1: open circuit, or no sensor installed. |
| IVT Geo 500/600 series ground source heat pump[177] | 5202Outdoor sensor T1: short circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5203Outdoor sensor T1 faulty (alarm stage). |
| IVT Geo 312/412 ground source heat pump[178] | 3091Thermistor in the room unit (RC100/CR10) for heating circuit 1 is faulty while the bus works. |
| IVT Geo 312/412 ground source heat pump[178] | 3092Thermistor in the room unit (RC100/CR10) for heating circuit 2 is faulty while the bus works. |
| IVT Geo 312/412 ground source heat pump[178] | 3093Thermistor in the room unit (RC100/CR10) for heating circuit 3 is faulty while the bus works. |
| IVT Geo 312/412 ground source heat pump[178] | 3094Thermistor in the room unit (RC100/CR10) for heating circuit 4 is faulty while the bus works. |
| IVT Geo 312/412 ground source heat pump[178] | 5201Outdoor sensor T1: open circuit, or no sensor installed. |
| IVT Geo 312/412 ground source heat pump[178] | 5202Outdoor sensor T1: short circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5203Outdoor sensor T1 faulty (alarm stage). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 1037Outdoor sensor faulty or its cable broken; the unit heats on a fallback value meanwhile. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3091Thermistor in the room unit for heating circuit 1 is faulty while the bus works; a wrongly configured external room sensor gives the same code. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3092Thermistor in the room unit for heating circuit 2 is faulty while the bus works; a wrongly configured external room sensor gives the same code. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3093Thermistor in the room unit for heating circuit 3 is faulty while the bus works; a wrongly configured external room sensor gives the same code. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3094Thermistor in the room unit for heating circuit 4 is faulty while the bus works; a wrongly configured external room sensor gives the same code. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5201Outdoor sensor T1: open circuit in sensor or cable. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5202Outdoor sensor T1: short circuit in sensor or cable. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5203Outdoor sensor T1 faulty (alarm stage). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5395Air inlet sensor TL2: open circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5408Air inlet sensor TL2: open circuit (warning). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5409Air inlet sensor TL2: short circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5410Air inlet sensor TL2 faulty (alarm stage). |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 2 + Timer 2Room (return air) thermistor open or short circuit (code 02/03): measure the thermistor and its plug. red + green ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 3 + Timer 4Outdoor air temperature thermistor open or short circuit (code 0A/0b). red + green ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 2 + Timer 2Room thermistor open or short circuit (02/03). green + orange ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 3 + Timer 4Outdoor air thermistor fault (0A/0b). green + orange ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 4 flashesOutdoor air temperature thermistor fault. red ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 02Room (return air) thermistor open circuit. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 03Room (return air) thermistor short circuit. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 0AOutdoor air thermistor open circuit. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 0bOutdoor air thermistor short circuit. |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | E2:00Return air thermistor open circuit or missing. |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | E3:00Return air thermistor short circuit. |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | EA:00Outdoor ambient thermistor open circuit. |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | EB:00Outdoor ambient thermistor short circuit (listed only in the unknown-publisher list). |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation blinking + Timer 4Outdoor air thermistor open circuit. green + red ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation blinking + Timer 4 + Swing blinkingOutdoor air thermistor short circuit. green + red + yellow ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation 2 + Timer blinkingRoom air thermistor open circuit. green + red ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation 2 + Timer blinking + Swing blinkingRoom air thermistor short circuit. green + red + yellow ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wall-mounted multi indoor units (older, UK; two-stage lamp code)[186] | Red 2 + Green blinking, test button: Red blinking + Green 2Indoor sensor fault group; after the test button: room air thermistor. red + green ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wall-mounted multi indoor units (older, UK; two-stage lamp code)[186] | Red blinking + Green 2, test button: Red 6 + Green blinkingOutdoor thermistor group; after the test button: outdoor air thermistor. red + green ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 9–30 (older, one red LED)[187] | LED red 4Outdoor air thermistor fault. red ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 36–54 (older, one red LED)[188] | LED red 4Outdoor air thermistor fault. red ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu non-inverter outdoor unit PCB (older, two red LEDs)[189] | LED 1 4 + LED 2 steadyOutdoor air thermistor fault. red ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter multi outdoor unit AOY30 (older, LEDs A–D)[190] | LED A–D 4 flashesOutdoor air thermistor fault. red ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red 1 short + Green rapid (G)Room sensor fault. red + green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red 2 short + Green rapidRoom sensor open or failed (groups A, B, D, E, F, G). red + green ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red 2 short + Green rapid + Yellow rapid (E, F)Room sensor short circuit. red + green + yellow ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red 3 short + Green long (C)Room sensor fault. red + green ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red rapid + Green 4 short (F)Outdoor temperature sensor open circuit. red + green ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red rapid + Green 4 short + Yellow rapid (F)Outdoor temperature sensor short circuit. red + green + yellow ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu AIRSTAGE J-II VRF – wired and simple remote controllers UTY-RNK*, UTY-RSK*, UTY-RHK* (error code on the display)[197] | 41Room (return air) thermistor open or short at power-on. Measure it off the board (about 33.6 kΩ at 0 °C, 10 kΩ at 25 °C) and check 5 V DC at its PCB input. |
| Fujitsu AIRSTAGE J-II VRF – wired and simple remote controllers UTY-RNK*, UTY-RSK*, UTY-RHK* (error code on the display)[197] | Thermo sensor indicator flashingWired RC UTY-RNK*: the thermistor built into the remote controller is open or short. Replace the remote controller. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 41Indoor room thermistor fault. Measure it (about 10 kΩ at 25 °C) and its 5 V supply. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 74Outdoor air thermistor TH3 open or short (E.74.1). |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.74.1Outdoor air thermistor TH3 open or short. Measure it (thermistor C: about 10 kΩ at 25 °C, 33.6 kΩ at 0 °C) and 5 V DC at the PCB input. |
| Fujitsu AIRSTAGE J-II VRF – indoor units (Operation/Timer/Filter lamps)[199] | Operation 4 + Timer 1 + Filter flashing fastRoom temperature thermistor error (code 41). Measure it (about 10 kΩ at 25 °C). The Filter lamp flickers fast (0.1 s) as the error marker; Operation and Timer flash their counts in turn. (The manual does not give the colour.) green + orange + red ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
The air temperature sensor is faulty, or its connection is broken.
Check: Measure the sensor resistance and compare with the table for the sensor type. Check cable and terminal and replace a faulty sensor.
Lost analog signal (live zero)
| Controller | Code |
|---|---|
| Danfoss VLT FC 103[14] | A2 |
| Copeland Digital Compressor Controller[61] | 5 flashes red ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED blue 1 blue ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A2 |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | Cable break |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED orange 11 orange ●●●●●●●●●●● · 0.25 s on, 0.25 s off · pause 3 s |
| Temperzone UC7 unit controller[101] | F32 |
| BAC Nexus modular hybrid cooler (NXF controls)[172] | Al_CableBreak_EBM_n |
| BAC TrilliumSeries adiabatic cooler TRF[174] | 17 |
| IVT Geo 500/600 series ground source heat pump[177] | 5980A PWM signal (probably the circulation pump control or feedback) is outside its allowed range. |
An analog input (4–20 mA, 0–10 V or a PWM set point) has dropped well below its set minimum, which the drive or fan reads as a broken wire or a dead transmitter or controller output.
Check: Measure the signal at the terminal and check the wiring, the transmitter supply and the controller output; check that the input is set to current or voltage to match the signal and that the low limit is right.
Defrost sensor fault (S5)
| Controller | Code |
|---|---|
| Danfoss ERC 21X[1] | E27 |
| Danfoss EKC 202A/B/C[2] | E27 |
| Danfoss AK-CC 550A[3] | E27 |
| Carel MPX[6] | E1 |
| Carel MasterCella[7] | E1 |
| Dixell XW270L/XW271L[9] | P2 |
| Zanotti GM/GS[10] | E2 |
| Carel ir33[11] | E1 |
| Dixell XR60CX[12] | P2 |
| Eliwell ID 974[13] | E2 |
| Carel Heos[18] | Eb |
| Carel ir33+ VCC[20] | E1 |
| Carel SmartCella / SmartCella 3PH[24] | E1 |
| Heatcraft Beacon II[30] | E2 |
| Heatcraft Beacon II[30] | DFSEN |
| Danfoss AK-CC 450[32] | E27 |
| Danfoss AK-CC 450[32] | E37 |
| Danfoss AK-CC 550 / 550B[33] | E27 |
| Danfoss AK-CC 550 / 550B[33] | E37 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | E27 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | E37 |
| Danfoss AK-CC55 Water Loop[35] | E27 |
| Danfoss AK-CC 750[36] | S5-1A sensor error |
| Danfoss Optyma control AK-RC 113[39] | E1 |
| Danfoss EKC 202D1[41] | E27 |
| Danfoss EKC 202D1[41] | E37 |
| Danfoss AK-RC 251[47] | E2 |
| Dixell XM669K/XM679K[50] | P2 |
| Dixell XR06CX[51] | P2 |
| Dixell XR35CX[52] | P2 |
| Dixell XR460C[53] | P3 |
| Dixell XR70CX[54] | P2 |
| Dixell XW60K/XW60L[55] | P2 |
| Dixell XWi70K[56] | P2 |
| Danfoss DHP heat pumps (DHP-A/AL/C/H/L)[76] | DEFROST SENSOR |
| Secop SLV controller 105N46xx[81] | E27 |
| AHT electronic controller (plug-in cases, standard)[82] | F2 |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | F2 |
| AHT GD-Cooler (GD-XLS, GD-XL)[84] | P2 |
| Pego ECP200 EXPERT PULSE[89] | E1 |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | E1 |
| Störk-Tronic ST121 / ST501 / ST551[93] | E2L |
| Störk-Tronic ST121 / ST501 / ST551[93] | E2H |
| Temperzone UC8 unit controller[100] | F16 |
| Temperzone UC7 unit controller[101] | F16 |
| Goodman DX20VC inverter condensing unit[105] | E27 |
| Evco EVK214[109] | Pr2 |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | Err2 |
| Full Gauge TC-900E Log[118] | Err2 |
| Full Gauge TC-940R[119] | Er2 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Prb5 |
| Temperzone UC8 unit controller[100] | F18 |
| Temperzone UC7 unit controller[101] | F18 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E04 |
| ActronAir Aires and Advance 19–25 kW[137] | E4 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | EH 61 |
| ActronAir Nexus Touch Controller WTC-01[139] | E5 |
| ActronAir UltraSlim 2 ducted split system[140] | E3 |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | E02 |
| Danfoss ETC (True cabinets)[142] | E2 |
| Carel PQ (True cabinets)[144] | E1 |
| Dixell XR/XW (True cabinets)[145] | P2 |
| LAE AR2/BR1/BIT25 and BR+/CD25/TM (True cabinets)[146] | E2 |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | E2 |
| Dixell XR03CX/XR04CX (Hillphoenix display cases)[159] | P2 |
| Carel MPXzero (Hillphoenix display cases)[160] | E2 |
| HTPG EcoNet enabled unit coolers[162] | A101 |
| HTPG EcoNet enabled unit coolers[162] | A102 |
| LAE AT1-5/AT2-5[166] | E2 |
| Pego 202BASE electronic board[167] | E1 |
| alpha innotec BWP 190S/260S DHW heat pump[168] | Er2 |
| Vaillant aroSTOR plus VWL B/BM 200/6, 260/6[171] | P05 |
The sensor on the evaporator is faulty or disconnected. The defrost can then not end on temperature.
Check: Measure the sensor and the cable. Check that the defrost works until the sensor has been replaced.
Suction gas or outlet sensor fault
| Controller | Code |
|---|---|
| Danfoss AK-CC 550A[3] | E24 |
| Danfoss Optyma Plus[4] | E33 |
| Carpigiani AES PSP[15] | AL12 |
| Carpigiani AES PSP[15] | AL13 |
| Carel EVD evolution / EVD evolution twin[16] | Probe S2 |
| Carel EVD ice / EVD mini[17] | A2 |
| Carel Heos[18] | EA |
| Carel MPXone[21] | dA2 |
| Carel pRack pR300[22] | ALA25 |
| Carel pRack pR300T (transcritical CO2)[23] | ALA25 |
| Copeland EXD-SH1/2[26] | 1E1 |
| Copeland EXD-SH1/2[26] | 2E1 |
| Heatcraft Beacon II[30] | E3 |
| Heatcraft Beacon II[30] | STSEN |
| Sanhua SEC60x[31] | toP |
| Sanhua SEC60x[31] | tSt |
| Danfoss AK-CC 550 / 550B[33] | E23 |
| Danfoss AK-CC 550 / 550B[33] | E24 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | E24 |
| Danfoss AK-CC 750[36] | S2A sensor error |
| Danfoss AK-PC 781A[37] | SsA sensor error |
| Danfoss AK-PC 782A/782B[38] | SsA sensor error |
| Danfoss EIM 365[40] | S2 Error |
| Danfoss EKE 1A/1B/1C/1D[43] | E024 |
| Danfoss EKE 1A/1B/1C/1D[43] | A981 |
| Danfoss EKE 100[44] | A18 |
| Danfoss EKE 100[44] | A27 |
| Danfoss Optyma iCO2[46] | E33 |
| Dixell XEV12D[49] | P1 |
| Dixell XM669K/XM679K[50] | P6 |
| Carel µC2SE for process chiller[59] | ES1 |
| Carel µChiller[60] | A24 |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | C5 |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | J5 |
| LG Multi V 5 VRF outdoor units[77] | CH46 |
| Pego ECP200 EXPERT PULSE[89] | E4 |
| Temperzone UC8 unit controller[100] | F14 |
| Temperzone UC8 unit controller[100] | F20 |
| Temperzone UC7 unit controller[101] | F14 |
| Temperzone UC7 unit controller[101] | F20 |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | P2 |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | P9 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | F01 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | F12 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | F01 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | F12 |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | 18 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Prb3 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Prb4 |
| RDM Intuitive Superpack / Transcritical Superpack[132] | ShFt |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E18 |
| ActronAir Aires and Advance 19–25 kW[137] | E18 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | EC 56 |
| ActronAir UltraSlim 2 ducted split system[140] | E4 |
| True Ice TI/TCIM ice machines[147] | E1 |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er19 |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er20 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er19 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er20 |
| HTPG EcoNet enabled unit coolers[162] | A100 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | F.514 |
| Vaillant aroSTOR plus VWL B/BM 200/6, 260/6[171] | P07 |
| LAE BR1-27/BR1-28/BR5-A/BR5-B/BD1-28/CD25[165] | E2 |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp A 2 flashesP2/P9 indoor pipe sensor error (wireless: count flashes after self-check; pattern A = indoor unit, starts after about 2.5 s off). Alarm symbol: green ●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | Light block Operation + Timer alternate blinking, Ready offIndoor temperature sensor error (TCJ, TC1, TC2, TA, TF; F01–F11). (Ready off.) (The manual does not give the colour.) Alarm symbol: green ● → yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| IVT AirX air-to-water heat pump[175] | 5426Suction gas sensor TR5: open circuit. |
| IVT AirX air-to-water heat pump[175] | 5427Suction gas sensor TR5: short circuit. |
| IVT AirX air-to-water heat pump[175] | 5428Suction gas sensor TR5: faulty (alarm stage). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5426Suction gas sensor TR5: open circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5427Suction gas sensor TR5: short circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5428Suction gas sensor TR5: faulty (alarm stage). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5628Suction gas sensor TR5 fault, LG code 46 (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5629Suction gas sensor TR5 fault, LG code 46 (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5426Suction gas sensor TR5: open circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5427Suction gas sensor TR5: short circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5428Suction gas sensor TR5: faulty (alarm stage). |
| IVT Geo 312/412 ground source heat pump[178] | 5426Suction gas sensor TR5: open circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5427Suction gas sensor TR5: short circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5428Suction gas sensor TR5: faulty (alarm stage). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5426Suction gas sensor TR5: open circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5427Suction gas sensor TR5: short circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5428Suction gas sensor TR5: faulty (alarm stage). |
| Fujitsu AIRSTAGE J-II VRF – wired and simple remote controllers UTY-RNK*, UTY-RSK*, UTY-RHK* (error code on the display)[197] | 42Indoor heat exchanger thermistor (inlet or outlet) open or short. Measure it off the board (about 168.6 kΩ at 0 °C, 49.8 kΩ at 25 °C) and check 5 V DC at its PCB input. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 42Indoor heat exchanger thermistor fault. Measure it (about 49.8 kΩ at 25 °C) and its 5 V supply. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 75Outdoor suction gas thermistor TH4 open or short (E.75.1). |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.75.1Suction gas thermistor TH4 open or short. Measure it (thermistor B: about 16.1 kΩ at 0 °C) and 5 V DC at the PCB input. |
| Fujitsu AIRSTAGE J-II VRF – indoor units (Operation/Timer/Filter lamps)[199] | Operation 4 + Timer 2 + Filter flashing fastIndoor heat exchanger thermistor error (code 42). Measure it (about 49.8 kΩ at 25 °C). The Filter lamp flickers fast (0.1 s) as the error marker; Operation and Timer flash their counts in turn. (The manual does not give the colour.) green + orange + red ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
The temperature sensor at the evaporator outlet or on the suction line is faulty or disconnected, so the superheat cannot be calculated correctly.
Check: Measure the sensor and the cable and check the sensor contact with the pipe. Replace a faulty sensor.
Extra or configurable sensor fault
| Controller | Code |
|---|---|
| Carel ir33[11] | E2 |
| Carel ir33[11] | E3 |
| Carel ir33[11] | E4 |
| Dixell XR60CX[12] | P3 |
| Dixell XR60CX[12] | P4 |
| Eliwell ID 974[13] | E3 |
| Carpigiani AES PSP[15] | AL05 |
| Carpigiani AES PSP[15] | AL07 |
| Carel EVD evolution / EVD evolution twin[16] | Probe S4 |
| Carel ir33 universale[19] | E02 |
| Carel ir33+ VCC[20] | E2 |
| Carel ir33+ VCC[20] | E3 |
| Carel ir33+ VCC[20] | E4 |
| Carel MPXone[21] | E1 |
| Carel MPXone[21] | E2 |
| Carel MPXone[21] | E3 |
| Carel MPXone[21] | E4 |
| Carel MPXone[21] | E5 |
| Carel MPXone[21] | E6 |
| Carel pRack pR300[22] | ALA01 |
| Carel pRack pR300T (transcritical CO2)[23] | ALA43 |
| Carel SmartCella / SmartCella 3PH[24] | E2 |
| Carel SmartCella / SmartCella 3PH[24] | E3 |
| Carel µRack[25] | AB2 |
| Carel µRack[25] | AB3 |
| Copeland ZSI scroll condensing units[28] | LED1 3 flashes green ●●● · 0.5 s on, 0.5 s off · pause 5 s (timing assumed, not stated in the manual) |
| Copeland EazyCool ZX (XCM25D)[5] | E03 |
| Copeland Large ZX 22–30 HP[29] | E02 |
| Copeland Large ZX 22–30 HP[29] | E03 |
| Heatcraft Beacon II[30] | A4 |
| Heatcraft Beacon II[30] | E5 |
| Heatcraft Beacon II[30] | INFLT |
| Heatcraft Beacon II[30] | ODSEN |
| Danfoss AK-CC 450[32] | E28 |
| Danfoss AK-CC 450[32] | E38 |
| Danfoss AK-CC 550 / 550B[33] | E28 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | E28 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | E59 |
| Danfoss AK-CC55 Water Loop[35] | E50 |
| Danfoss AK-CC55 Water Loop[35] | E65 |
| Danfoss AK-CC 750[36] | Product temp. A sensor error |
| Danfoss AK-PC 781A[37] | S4A sensor error |
| Danfoss AK-PC 782A/782B[38] | Sgc sensor error |
| Danfoss EIM 365[40] | S4 Error |
| Danfoss EKC 326A[42] | E15 |
| Danfoss EKC 326A[42] | E16 |
| Danfoss EKE 1A/1B/1C/1D[43] | E025 |
| Danfoss EKE 1A/1B/1C/1D[43] | E026 |
| Danfoss EKE 100[44] | A19 |
| Danfoss EKE 100[44] | A36 |
| Danfoss ERC 21X[1] | E30 |
| Danfoss Optyma Plus[4] | E30 |
| Danfoss Optyma Plus[4] | E31 |
| Danfoss Optyma Plus[4] | E32 |
| Danfoss Optyma Plus Module B Plus (P02)[45] | Y1-R3 yellow ● → red ●●● · 1 s on, 1 s off · 1 s between colours · pause 3 s (timing assumed, not stated in the manual) |
| Danfoss Optyma Plus Module B Plus (P02)[45] | Y1-R4 yellow ● → red ●●●● · 1 s on, 1 s off · 1 s between colours · pause 3 s (timing assumed, not stated in the manual) |
| Danfoss Optyma iCO2[46] | E20 |
| Danfoss Optyma iCO2[46] | E31 |
| Danfoss Optyma iCO2[46] | E32 |
| Danfoss Optyma iCO2[46] | E40 |
| Danfoss AK-RC 251[47] | E3 |
| Dixell XC645D[48] | P3 |
| Dixell XC645D[48] | P4 |
| Dixell XC645D[48] | P5 |
| Dixell XM669K/XM679K[50] | P3 |
| Dixell XM669K/XM679K[50] | P4 |
| Dixell XM669K/XM679K[50] | CPF |
| Dixell XR35CX[52] | P3 |
| Dixell XR35CX[52] | P4 |
| Dixell XR70CX[54] | P3 |
| Dixell XR70CX[54] | P4 |
| Dixell XW60K/XW60L[55] | P3 |
| Dixell XW60K/XW60L[55] | P4 |
| Dixell XWi70K[56] | P3 |
| Dixell XWi70K[56] | P4 |
| Carel µC2SE for process chiller[59] | E1 |
| Carel µC2SE for process chiller[59] | E2 |
| Carel µC2SE for process chiller[59] | E4 |
| Carel µChiller[60] | A05 |
| Carel µChiller[60] | A06 |
| Carel µChiller[60] | A23 |
| Copeland Digital Compressor Controller[61] | 6 flashes red ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland PerformanceAlert diagnostic module[62] | 11 flashes yellow ●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Protection (Discus)[63] | LED green 3 green ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Protection (Discus)[63] | LED green 4 green ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland compressor electronics communications (20–40 ton scroll)[65] | LED green 4 green ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED green 11 green ●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | J3 |
| Danfoss DHP heat pumps (DHP-A/AL/C/H/L)[76] | SUPPLY LINE SENSOR |
| Danfoss DHP heat pumps (DHP-A/AL/C/H/L)[76] | RETURN LINE SENSOR |
| Danfoss DHP heat pumps (DHP-A/AL/C/H/L)[76] | HOT WATER SENSOR |
| Danfoss DHP heat pumps (DHP-A/AL/C/H/L)[76] | SENSOR COOLING |
| LG Multi V 5 VRF outdoor units[77] | CH41 |
| NIBE F1255 ground source heat pump[78] | 2 |
| NIBE F1255 ground source heat pump[78] | 3 |
| NIBE F1255 ground source heat pump[78] | 11 |
| NIBE F1255 ground source heat pump[78] | 12 |
| Secop SLV controller 105N46xx[81] | E28 |
| Secop SLV controller 105N46xx[81] | E29 |
| AHT electronic controller (plug-in cases, standard)[82] | F3 |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | F4 |
| RDM DMTouch / miniDM[91] | Probe Fault |
| RDM DMTouch / miniDM[91] | Cond N TD Discharge Probe Error |
| RDM DMTouch / miniDM[91] | Cond N TD LiqRtn Probe Error |
| RDM DMTouch / miniDM[91] | Cond N TD Ambient Probe Error |
| Störk-Tronic ST121 / ST501 / ST551[93] | E3L |
| Störk-Tronic ST121 / ST501 / ST551[93] | E3H |
| Störk-Tronic ST121 / ST501 / ST551[93] | E4L |
| Störk-Tronic ST121 / ST501 / ST551[93] | E4H |
| Kriwan INT69 F Diagnose[94] | LED red 3 / orange 4 red ●●● → orange ●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 PYF Diagnose[95] | LED red 3 / orange 4 red ●●● → orange ●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 PYF Diagnose[95] | LED red 3 / orange 5 red ●●● → orange ●●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 PYF Diagnose[95] | LED red 5 / orange 4 red ●●●●● → orange ●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 PYF Diagnose[95] | LED red 6 / orange 2 red ●●●●●● → orange ●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 YF Diagnose[98] | LED red 3 / orange 4 red ●●● → orange ●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 YF Diagnose[98] | LED red 3 / orange 5 red ●●● → orange ●●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Temperzone UC8 unit controller[100] | F15 |
| Temperzone UC8 unit controller[100] | F17 |
| Temperzone UC8 unit controller[100] | F18 |
| Temperzone UC8 unit controller[100] | F19 |
| Temperzone UC7 unit controller[101] | F15 |
| Temperzone UC7 unit controller[101] | F17 |
| Temperzone UC7 unit controller[101] | F18 |
| Temperzone UC7 unit controller[101] | F19 |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 51** |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | U3 |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | U4 |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | U3 |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | U4 |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | UH |
| Goodman DX20VC inverter condensing unit[105] | E23 |
| Goodman DX20VC inverter condensing unit[105] | E28 |
| Goodman DX20VC inverter condensing unit[105] | E29 |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | Outdoor Air Temp Sensor Failure |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | Drop Leg Temp Sensor Failure |
| Evco EV3203[107] | Pr2 |
| Evco EVK214[109] | Pr3 |
| Evco EV3 HP / EVD HP (heat pump)[110] | EA01 |
| Evco EV3 CHILL / HPRU (chiller, heat pump)[111] | EA01 |
| Evco EV3 MVC / EVD MVC (air handling)[112] | AL03 |
| Hitachi multi-split heat pump[113] | 20 |
| Thermia Atella / Robust[114] | OUTDOOR SENSOR |
| Thermia Atella / Robust[114] | SUPPLY LINE SENSOR |
| Thermia Atella / Robust[114] | RETURN LINE SENSOR |
| Thermia Atella / Robust[114] | HOT WATER SENSOR |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | Err3 |
| Full Gauge TC-900E Log[118] | Err3 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | F04 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | F06 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | F04 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | F06 |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | 19 |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | 1B |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A10 |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | F25 |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | F26 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Prb6 |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | Prb1–Prb6 |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | rhFt |
| RDM Mercury AC and roof top unit controllers[130] | Evap. In Temp Fault |
| RDM Mercury AC and roof top unit controllers[130] | Evap. Out Temp Fault |
| RDM Mercury AC and roof top unit controllers[130] | Cond. Out Temp Fault |
| RDM Mercury AC and roof top unit controllers[130] | Evap. In Probe Fault |
| RDM Mercury AC and roof top unit controllers[130] | Evap. Out Probe Fault |
| RDM Mercury AC and roof top unit controllers[130] | Cond. Out Probe Fault |
| RDM Intuitive / Mercury pack and condenser controllers[131] | Prb 1–Prb 5 |
| RDM Intuitive Superpack / Transcritical Superpack[132] | Prb 1–Prb 8 |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 85 |
| RDM ML Controller case controller[134] | Prb1–Prb4 |
| Temperzone UC6 unit controller[135] | 5 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E07 |
| ActronAir Aires and Advance 19–25 kW[137] | E7 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | EC 52 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | EC 53 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | EC 54 |
| ActronAir Nexus Touch Controller WTC-01[139] | F2 |
| ActronAir UltraSlim 2 ducted split system[140] | E5 |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | E03 |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | E04 |
| Carel PQ (True cabinets)[144] | E2 |
| Dixell XR/XW (True cabinets)[145] | P3 |
| LAE AR2/BR1/BIT25 and BR+/CD25/TM (True cabinets)[146] | E3 |
| True Ice TI/TCIM ice machines[147] | E2 |
| True Ice TI/TCIM ice machines[147] | E3 |
| True Ice TI/TCIM ice machines[147] | E4 |
| True Ice TI/TCIM ice machines[147] | E9 |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | E3 |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | E4 |
| Taylor frozen beverage freezers C300, C302, C303/C314, 345/346/349/355[149] | THERMISTOR SHORT |
| Taylor frozen beverage freezers C300, C302, C303/C314, 345/346/349/355[149] | THERMISTOR OPEN |
| Taylor C392/C393/C394 frozen beverage freezers[150] | Thermistor Open/Shorted |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | HOPPER THERMISTOR FAIL |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | BARREL THERMISTOR FAIL |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | HOPPER THERM FAIL |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | BRL THERM FAIL |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | TH |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | HOPPER THERMISTOR FAIL |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | BARREL THERMISTOR FAIL |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | SHRT |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | OPEN |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | OVER |
| Taylor 736 soft serve freezer[153] | TEV INT. |
| Taylor 736 soft serve freezer[153] | TEV S.C. |
| Taylor 736 soft serve freezer[153] | TEC INT. |
| Taylor 736 soft serve freezer[153] | TEC S.C. |
| Taylor 736 soft serve freezer[153] | TEF INT. |
| Taylor 736 soft serve freezer[153] | TEF S.C. |
| Taylor 736 soft serve freezer[153] | CTS INT. |
| Taylor 736 soft serve freezer[153] | CTS S.C. |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er01 |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er02 |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er03 |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er04 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er01 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er02 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er03 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er04 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er05 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er06 |
| HTPG EcoNet enabled unit coolers[162] | A104 |
| HTPG EcoNet enabled unit coolers[162] | A105 |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Failed Sensor Or Bad Wiring |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | Outdoor Temp Fault |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | Drop Leg Temp Fault |
| alpha innotec BWP 190S/260S DHW heat pump[168] | Er3 |
| alpha innotec WWB 190 DHW heat pump[169] | E1 |
| alpha innotec WWB 190 DHW heat pump[169] | E2 |
| alpha innotec WWB 190 DHW heat pump[169] | E3 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | F.517 |
| Vaillant aroSTOR plus VWL B/BM 200/6, 260/6[171] | P01 |
| Vaillant aroSTOR plus VWL B/BM 200/6, 260/6[171] | P02 |
| Vaillant aroSTOR plus VWL B/BM 200/6, 260/6[171] | P03 |
| BAC Nexus modular hybrid cooler (NXF controls)[172] | Al_LWT_ProbeErr |
| BAC Nexus modular hybrid cooler (NXF controls)[172] | Al_OAT_ProbeErr |
| BAC TrilliumSeries adiabatic cooler TRF[174] | 12 |
| BAC TrilliumSeries adiabatic cooler TRF[174] | 13 |
| LAE BR1-27/BR1-28/BR5-A/BR5-B/BD1-28/CD25[165] | E3 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Running lamp 5, timer offOutdoor EEPROM error (EC 51) or outdoor sensor T3, T4, TP or T2B open/short (EC 52-EC 56); read the code. (The manual does not give the colour.) Alarm symbol: green ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Kriwan INT69 F Diagnose[94] | LED green 3 / orange 4Warning: open or short circuit on temperature input 1. Symbol: green ●●● → orange ●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D802+D803 yellow (3 s on / 0.5 s off)Current error: Discharge temperature sensor TD error (19). Alarm symbol: yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D800+D802+D803 yellow (3 s on / 0.5 s off)Current error: Outdoor air temperature sensor TO error (1B); back-up operation without indoor error display. Alarm symbol: yellow ● → yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D804 yellow (3 s on / 0.5 s off)Current error: Gas pipe sensor TGa (unit A) error (1C); other rooms run normally. Alarm symbol: yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D800+D804 yellow (3 s on / 0.5 s off)Current error: Gas pipe sensor TGb (unit B) error (1C). Alarm symbol: yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D801+D804 yellow (3 s on / 0.5 s off)Current error: Gas pipe sensor TGc (unit C) error (1C). Alarm symbol: yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D800+D801+D804 yellow (3 s on / 0.5 s off)Current error: Gas pipe sensor TGd (unit D) error (1C). Alarm symbol: yellow ● → yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D802+D804 yellow (3 s on / 0.5 s off)Current error: Gas pipe sensor TGe (unit E) error (1C). Alarm symbol: yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp B 3 flashesU3/U4 outdoor thermistor open or short (pattern B = outdoor/other unit: lamp on for about 3 s, then the flashes). Alarm symbol: green ●●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | Light block Operation + Timer alternate blinking, Ready onOutdoor temperature or pressure sensor error or sensor wiring error (F04–F24). (Ready lit.) (The manual does not give the colour.) Alarm symbol: green ● → yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| IVT AirX air-to-water heat pump[175] | 3141The relative humidity sensor in the room unit for heating circuit 1 is broken. |
| IVT AirX air-to-water heat pump[175] | 3142The relative humidity sensor in the room unit for heating circuit 2 is broken. |
| IVT AirX air-to-water heat pump[175] | 3143The relative humidity sensor in the room unit for heating circuit 3 is broken. |
| IVT AirX air-to-water heat pump[175] | 3144The relative humidity sensor in the room unit for heating circuit 4 is broken. |
| IVT AirX air-to-water heat pump[175] | 5538Condensate drip tray temperature sensor TA4: open circuit. |
| IVT AirX air-to-water heat pump[175] | 5539Condensate drip tray temperature sensor TA4: short circuit. |
| IVT AirX air-to-water heat pump[175] | 5540Condensate drip tray temperature sensor TA4: faulty (alarm stage). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3141The relative humidity sensor in the room unit for heating circuit 1 is broken. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3142The relative humidity sensor in the room unit for heating circuit 2 is broken. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3143The relative humidity sensor in the room unit for heating circuit 3 is broken. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3144The relative humidity sensor in the room unit for heating circuit 4 is broken. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5538Condensate drip tray temperature sensor TA4: open circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5539Condensate drip tray temperature sensor TA4: short circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5540Condensate drip tray temperature sensor TA4: faulty (alarm stage). |
| IVT Geo 500/600 series ground source heat pump[177] | 3141The relative humidity sensor in the room unit is broken (one code per heating circuit). |
| IVT Geo 500/600 series ground source heat pump[177] | 3142The relative humidity sensor in the room unit is broken (one code per heating circuit). |
| IVT Geo 500/600 series ground source heat pump[177] | 3143The relative humidity sensor in the room unit is broken (one code per heating circuit). |
| IVT Geo 500/600 series ground source heat pump[177] | 3144The relative humidity sensor in the room unit is broken (one code per heating circuit). |
| IVT Geo 500/600 series ground source heat pump[177] | 5946No signal from flow sensor TM0. |
| IVT Geo 500/600 series ground source heat pump[177] | 5947Short circuit in flow sensor TM0. |
| IVT Geo 500/600 series ground source heat pump[177] | 5948Signal from flow sensor TM0 outside the allowed range. |
| IVT Geo 312/412 ground source heat pump[178] | 3141The relative humidity sensor in the room unit is broken (one code per heating circuit). |
| IVT Geo 312/412 ground source heat pump[178] | 3142The relative humidity sensor in the room unit is broken (one code per heating circuit). |
| IVT Geo 312/412 ground source heat pump[178] | 3143The relative humidity sensor in the room unit is broken (one code per heating circuit). |
| IVT Geo 312/412 ground source heat pump[178] | 3144The relative humidity sensor in the room unit is broken (one code per heating circuit). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3141The relative humidity sensor in the room unit for heating circuit 1 is broken. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3142The relative humidity sensor in the room unit for heating circuit 2 is broken. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3143The relative humidity sensor in the room unit for heating circuit 3 is broken. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3144The relative humidity sensor in the room unit for heating circuit 4 is broken. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5538Condensate drip tray temperature sensor TA4: open circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5539Condensate drip tray temperature sensor TA4: short circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5540Condensate drip tray temperature sensor TA4: faulty (alarm stage). |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 3 + Timer 7Heat sink thermistor on the inverter PCB is faulty (code 0E). red + green ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 3 + Timer 7Heat sink thermistor in the outdoor inverter is faulty (0E). green + orange ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 8 flashesHeat sink thermistor fault. red ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 0EHeat sink thermistor fault on newer models; the older UK guide lists outdoor high pressure under this code. |
| Fujitsu inverter outdoor unit PCB, models 36–54 (older, one red LED)[188] | LED red 8Heat sink thermistor fault. red ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
A sensor input whose job is set by a parameter (often the condenser, a second evaporator, the product or an antifreeze sensor) reads out of range, or the sensor is disconnected or short-circuited.
Check: Look up which job the input has in the controller set-up, check that the sensor type (NTC/PTC) matches the sensor fitted, measure its resistance against the sensor table and check cables and terminals; an unused input should be set as not present.
Pressure transmitter fault
| Controller | Code |
|---|---|
| Danfoss AK-CC 550A[3] | E20 |
| Danfoss Optyma Plus[4] | E39 |
| Danfoss Optyma Plus[4] | E20 |
| Copeland EazyCool ZX (XCM25D)[5] | E01 |
| Carel EVD evolution / EVD evolution twin[16] | Probe S1 |
| Carel EVD evolution / EVD evolution twin[16] | Probe S3 |
| Carel EVD ice / EVD mini[17] | A1 |
| Carel Heos[18] | ELP |
| Carel Heos[18] | EHP |
| Carel MPXone[21] | dA1 |
| Carel pRack pR300[22] | ALA02 |
| Carel pRack pR300[22] | ALA24 |
| Carel pRack pR300T (transcritical CO2)[23] | ALA02 |
| Carel pRack pR300T (transcritical CO2)[23] | ALA24 |
| Carel pRack pR300T (transcritical CO2)[23] | ALA44 |
| Carel µRack[25] | A19 |
| Carel µRack[25] | A21 |
| Copeland EXD-SH1/2[26] | 1E0 |
| Copeland EXD-SH1/2[26] | 2E0 |
| Copeland EazyCool ZX (XCM25D)[5] | E02 |
| Copeland Large ZX 22–30 HP[29] | E01 |
| Heatcraft Beacon II[30] | E4 |
| Heatcraft Beacon II[30] | SPSEN |
| Sanhua SEC60x[31] | PoP |
| Sanhua SEC60x[31] | PSt |
| Danfoss AK-CC 550 / 550B[33] | E20 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | E20 |
| Danfoss AK-CC 750[36] | Po sensor error |
| Danfoss AK-CC 750[36] | Pc sensor error |
| Danfoss AK-PC 781A[37] | P0A sensor error |
| Danfoss AK-PC 781A[37] | PcA sensor error |
| Danfoss AK-PC 782A/782B[38] | P0A sensor error |
| Danfoss AK-PC 782A/782B[38] | Pgc sensor error |
| Danfoss AK-PC 782A/782B[38] | Prec sensor error |
| Danfoss EIM 365[40] | Pe inp.error |
| Danfoss EKC 326A[42] | E20 |
| Danfoss EKC 326A[42] | E39 |
| Danfoss EKE 1A/1B/1C/1D[43] | E020 |
| Danfoss EKE 1A/1B/1C/1D[43] | E121 |
| Danfoss EKE 100[44] | A17 |
| Danfoss Optyma iCO2[46] | E39 |
| Danfoss Optyma iCO2[46] | E41 |
| Danfoss Optyma iCO2[46] | E42 |
| Dixell XC645D[48] | P1 |
| Dixell XC645D[48] | P2 |
| Dixell XEV12D[49] | P2 |
| Dixell XM669K/XM679K[50] | P5 |
| Dixell XM669K/XM679K[50] | PPF |
| Dixell XM669K/XM679K[50] | rPF |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 33 |
| Carel µChiller[60] | A19 |
| Carel µChiller[60] | A21 |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | JA |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | JC |
| LG Multi V 5 VRF outdoor units[77] | CH42 |
| LG Multi V 5 VRF outdoor units[77] | CH43 |
| Pego ECP200 EXPERT PULSE[89] | E5 |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | SUCTION PRESSURE OVER RANGE |
| Mayekawa MYPRO TOUCH (MYCOM screw compressor panel)[99] | DISCHARGE PRESSURE UNDER RANGE |
| Temperzone UC8 unit controller[100] | F12 |
| Temperzone UC8 unit controller[100] | F13 |
| Temperzone UC8 unit controller[100] | F34 |
| Temperzone UC7 unit controller[101] | F12 |
| Temperzone UC7 unit controller[101] | F13 |
| Temperzone UC7 unit controller[101] | F34 |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 52** |
| Goodman DX20VC inverter condensing unit[105] | E26 |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | Discharge Pressure Sensor Failure |
| Hitachi multi-split heat pump[113] | 21 |
| Hitachi multi-split heat pump[113] | 29 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | F23 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | F24 |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A12 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Prb7 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | rFt1 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | rFt2 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Transducer fault |
| RDM Intuitive / Mercury pack and condenser controllers[131] | trAn |
| RDM Intuitive / Mercury pack and condenser controllers[131] | Ft TrAn |
| RDM Intuitive Superpack / Transcritical Superpack[132] | trAn Ft |
| RDM Intuitive Superpack / Transcritical Superpack[132] | gSFt PgAS |
| RDM Intuitive Superpack / Transcritical Superpack[132] | rSFt PrEC |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 87 |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 88 |
| Temperzone UC6 unit controller[135] | 6 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E10 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E12 |
| ActronAir Aires and Advance 19–25 kW[137] | E10 |
| ActronAir Aires and Advance 19–25 kW[137] | E12 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | EC 5C |
| True Ice TI/TCIM ice machines[147] | E7 |
| True Ice TI/TCIM ice machines[147] | E8 |
| True Ice TI/TCIM ice machines[147] | E33 |
| True Ice TI/TCIM ice machines[147] | E34 |
| HTPG EcoNet enabled unit coolers[162] | A106 |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | Discharge Pressure Fault |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | F.546 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | F.703 |
| IVT AirX air-to-water heat pump[175] | 5432Low pressure transmitter JR0: open circuit, often caused by a brief voltage dip (warning). |
| IVT AirX air-to-water heat pump[175] | 5434Low pressure transmitter JR0 faulty (alarm). |
| IVT AirX air-to-water heat pump[175] | 5438High pressure transmitter JR1: open circuit, often temporary (warning). |
| IVT AirX air-to-water heat pump[175] | 5440High pressure transmitter JR1 faulty (alarm). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5432Low pressure transmitter JR0: open circuit, often caused by a brief voltage dip (warning). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5434Low pressure transmitter JR0 faulty (alarm). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5438High pressure transmitter JR1: open circuit, often temporary (warning). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5440High pressure transmitter JR1 faulty (alarm). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5662Pressure transmitter open or short-circuited, LG code 43 (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5663Pressure transmitter faulty, LG code 43 (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5432Low pressure transmitter JR0: open circuit (warning). |
| IVT Geo 500/600 series ground source heat pump[177] | 5434Low pressure transmitter JR0 faulty (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5438High pressure transmitter JR1 faulty. |
| IVT Geo 500/600 series ground source heat pump[177] | 5440High pressure transmitter JR1 faulty. |
| IVT Geo 312/412 ground source heat pump[178] | 5432Low pressure transmitter JR0: open circuit (warning). |
| IVT Geo 312/412 ground source heat pump[178] | 5434Low pressure transmitter JR0 faulty (alarm). |
| IVT Geo 312/412 ground source heat pump[178] | 5438High pressure transmitter JR1 faulty. |
| IVT Geo 312/412 ground source heat pump[178] | 5440High pressure transmitter JR1 faulty. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5432Low pressure transmitter JR0: open circuit, often caused by a brief voltage dip (warning). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5434Low pressure transmitter JR0 faulty (alarm). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5438High pressure transmitter JR1: open circuit, often temporary (warning). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5440High pressure transmitter JR1 faulty (alarm). |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 86Pressure sensor or high pressure switch error (E.86.1 discharge sensor, E.86.3 suction sensor, E.86.4 HP switch open at power-on). |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.86.1Discharge (high) pressure sensor error: below 0.3 V for 30 s, or 5.0 V or more, after power-on. Check the plug and cable, the sensor output (0.5 V at 0 MPa to 4.5 V at 5.0 MPa) and 5 V supply from the main PCB. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.86.3Suction (low) pressure sensor error: below 0.06 V for 30 s, or 5.0 V or more, after power-on. Check the plug and cable, the sensor output (0.5 V at 0 MPa to 3.5 V at 1.7 MPa) and 5 V supply from the main PCB. |
A pressure transmitter (suction or condensing pressure) gives no signal or an implausible one.
Check: Check the transmitter supply and signal, cable and connector, and compare with a gauge. Replace a faulty transmitter.
Sensors possibly swapped
| Controller | Code |
|---|---|
| Danfoss EKC 202D1[41] | A81 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | F15 |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A08 |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A11 |
| IVT AirX air-to-water heat pump[175] | 5446Supply and return pipes between indoor and outdoor unit are connected the wrong way round (seen from the temperatures; the pipes, not the sensors, are swapped). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5446Supply and return pipes between indoor and outdoor unit are connected the wrong way round (seen from the temperatures; the pipes, not the sensors, are swapped). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5446Supply and return pipes between indoor and outdoor unit are connected the wrong way round (seen from the temperatures; the pipes, not the sensors, are swapped). |
The readings from two temperature sensors (for example air-on S3 and air-off S4) are the wrong way round, which suggests the sensors have been mounted in each other's places or wired to the wrong terminals.
Check: Check where each sensor is mounted and which terminal it is wired to, and swap them if needed.
Defrost ended on time
| Controller | Code |
|---|---|
| Carel MPX[6] | Ed |
| Carel MasterCella[7] | Ed |
| Zanotti GM/GS[10] | Ad2 |
| Carel ir33[11] | Ed1 |
| Carel ir33[11] | Ed2 |
| Eliwell ID 974[13] | Ad2 |
| Carel Heos[18] | Ed1 |
| Carel ir33+ VCC[20] | Ed1 |
| Carel ir33+ VCC[20] | Ed2 |
| Carel MPXone[21] | Ed1 |
| Danfoss AK-CC 450[32] | Max Def.Time |
| Danfoss AK-CC 550 / 550B[33] | Max Def.Time |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | Z01 |
| Danfoss AK-CC55 Water Loop[35] | Z01 |
| Danfoss AK-CC 750[36] | Max defrost time exceeded |
| Danfoss AK-RC 251[47] | Adt |
| Secop SLV controller 105N46xx[81] | A06 |
| RDM DMTouch / miniDM[91] | Warning: Defrost term on time |
| Evco EV3203[107] | dFd |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | flashing dot |
| Full Gauge TC-900E Log[118] | flashing dot |
| Full Gauge TC-940R[119] | flashing dot |
| Carel PQ (True cabinets)[144] | Ed |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | Ed1 |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | Ed2 |
| HTPG EcoNet enabled unit coolers[162] | T001 |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Defrost terminated on Time |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | Dot lower right flashingLast defrost ended on maximum time (F14), not on temperature. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Full Gauge TC-940R[119] | Decimal point (lower right) flashingLast defrost ended on maximum time, not on temperature; stays until the next defrost. (The manual does not give the colour.) Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
The last defrost was stopped by the maximum time before the sensor reached the end temperature.
Check: Check that the defrost heats and that the sensor is correctly placed, and look for ice on the evaporator.
Evaporator iced up / air flow reduced
| Controller | Code |
|---|---|
| Danfoss AK-CC 550 / 550B[33] | A75 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | X02 |
| Danfoss AK-CC 750[36] | AD - Case X - Air flow reduced |
| Temperzone UC8 unit controller[100] | FROSt |
| Temperzone UC7 unit controller[101] | FROSt |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 1503 |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | P6 |
| Temperzone UC6 unit controller[135] | 7 |
| ActronAir Nexus Touch Controller WTC-01[139] | PH91 |
| alpha innotec BWP 190S/260S DHW heat pump[168] | Er8 |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp A 6 flashesP6 freezing/overheating protection of the indoor coil (wireless: count flashes after self-check; pattern A = indoor unit, starts after about 2.5 s off). Alarm symbol: green ●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| IVT AirX air-to-water heat pump[175] | 5293Dirty or blocked outdoor air coil or a stopped fan, detected on low pressure transmitter JR0. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5293Dirty or blocked outdoor air coil or a stopped fan, detected on low pressure transmitter JR0. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5293Dirty or blocked outdoor air coil or a stopped fan, detected on low pressure transmitter JR0. |
The adaptive defrost function has detected that the air flow through the evaporator has dropped sharply, usually because of heavy ice build-up, a stopped fan or a blocked coil.
Check: Look at the coil and the fans, check that defrosts start and end correctly (heater, drain, termination sensor) and that doors and night covers do not let in moist air.
Defrost fault
| Controller | Code |
|---|---|
| Danfoss AK-CC 450[32] | A5 |
| Danfoss AK-CC 550 / 550B[33] | A5 |
| Danfoss AK-CC 550 / 550B[33] | A74 |
| Danfoss AK-CC 550 / 550B[33] | A76 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | A05 |
| Danfoss AK-CC55 Water Loop[35] | A05 |
| Danfoss AK-CC 750[36] | Max defrost hold time |
| Danfoss AK-CC 750[36] | AD - Case X not defrosted |
| Secop SLV controller 105N46xx[81] | A05 |
| AHT electronic controller (plug-in cases, standard)[82] | dFr/F3 |
| RDM Mercury 3 Twin Coil[92] | Missed defrost |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Missed defrost |
| Danfoss ETC (True cabinets)[142] | E5 |
| True Ice TI/TCIM ice machines[147] | E26 |
| True Ice TI/TCIM ice machines[147] | E31 |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Did Not Exit Defrost |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | S.283 |
| IVT AirX air-to-water heat pump[175] | 5378Outdoor unit defrost failed, often because the heating water is too cold or the flow too low. |
| IVT AirX air-to-water heat pump[175] | 5463Defrost failed and the outdoor coil is blocked by ice; melt it carefully with warm water and improve the heating-water flow. |
| IVT AirX air-to-water heat pump[175] | 5505The heater in the condensate drip tray does not work, so the tray and drain can freeze. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5378Outdoor unit defrost failed, often because the heating water is too cold or the flow too low. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5463Defrost failed and the outdoor coil is blocked by ice; melt it carefully with warm water and improve the heating-water flow. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5505The heater in the condensate drip tray does not work, so the tray and drain can freeze. |
| IVT Geo 500/600 series ground source heat pump[177] | 5463Defrost alarm; IVT points to the heating-side flow (thermostats, filter). |
| IVT Geo 312/412 ground source heat pump[178] | 5463Defrost alarm; IVT points to the heating-side flow (thermostats, filter). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5378Outdoor unit defrost failed, often because the heating water is too cold or the flow too low. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5463Defrost failed and the outdoor coil is blocked by ice; melt it carefully with warm water and improve the heating-water flow. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5505The heater in the condensate drip tray does not work, so the tray and drain can freeze. |
The defrost did not work as expected (heater fault, no termination or too long).
Check: Check the defrost heaters and their current, the defrost sensor and the defrost settings.
Condensate drain overflow
| Controller | Code |
|---|---|
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | P10 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | P10 |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp A 4 flashesP4 drain float switch connector open (wireless: count flashes after self-check; pattern A = indoor unit, starts after about 2.5 s off). Alarm symbol: green ●●●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp A 5 flashesP5 drain pump error (water level) or PA forced compressor stop (wireless: count flashes after self-check; pattern A = indoor unit, starts after about 2.5 s off). Alarm symbol: green ●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| IVT AirX air-to-water heat pump[175] | 5450The condensate drain of the outdoor unit is blocked, so melt water can freeze in the unit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5450The condensate drain of the outdoor unit is blocked, so melt water can freeze in the unit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5450The condensate drain of the outdoor unit is blocked, so melt water can freeze in the unit. |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 2 + Timer 6Float switch in the indoor unit has operated (code 09): clear the drain, check the condensate pump and that the unit is level. red + green ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 2 + Timer 6Float switch tripped or condensate pump problem (09). green + orange ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 09Float switch has operated: blocked drain or condensate pump fault. |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | E9:00Float switch operated: high water level in the drain pan. |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation 4 + Timer blinkingDrain problem: float switch operated. green + red ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red 4 short + Green rapid (D, E, F)High water level in the drain pan. red + green ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red 6 short + Green rapid (G)High water level in the drain pan. red + green ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | A3Drain level fault on a VRV indoor unit: the float switch stayed up for more than 5 minutes although the drain pump ran, so the unit stops; check the drain pump, a blocked drain pipe or trap and the float switch. |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | AFThe drain float switch has tripped five times in a row, so the indoor unit reports a drain abnormality but keeps running; clean the drain pan and pipe and check the pump and, where fitted, the humidifier. |
| Fujitsu AIRSTAGE J-II VRF – wired and simple remote controllers UTY-RNK*, UTY-RSK*, UTY-RHK* (error code on the display)[197] | 53Drain abnormal: the float switch has been open for more than 3 min. Check the drain pump, the drain pipe and fall, the float switch and its connector; small wall units have no float switch, so the code points to the PCB. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 53Indoor drain abnormal: float switch open for more than 3 min. Check the drain pump, pipe and float switch. |
| Fujitsu AIRSTAGE J-II VRF – indoor units (Operation/Timer/Filter lamps)[199] | Operation 5 + Timer 3 + Filter flashing fastWater drain abnormal (code 53): float switch open for more than 3 min. The Filter lamp flickers fast (0.1 s) as the error marker; Operation and Timer flash their counts in turn. (The manual does not give the colour.) green + orange + red ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
The float switch in the indoor unit's drain pan has risen because condensate is not leaving fast enough, so the unit stops cooling to avoid water damage.
Check: Check the drain pump runs and its power and wiring, clear the drain pan, pump inlet and drain pipe of dirt or slime, check the pipe has fall and is not trapped or frozen, and check that the float switch moves freely.
Controller fault
| Controller | Code |
|---|---|
| Danfoss EKC 202A/B/C[2] | E1 |
| Danfoss Optyma Plus[4] | E1 |
| Carel MPX[6] | EA |
| Dixell XW270L/XW271L[9] | EE |
| Carel ir33[11] | Etc |
| Carel ir33[11] | EE |
| Carel ir33[11] | EF |
| Danfoss VLT FC 103[14] | A38 |
| Carel ir33 universale[19] | E19 |
| Copeland EXD-SH1/2[26] | ACF1 |
| Copeland EXD-SH1/2[26] | ACF2 |
| Danfoss AK-CC 450[32] | E1 |
| Danfoss AK-CC 550 / 550B[33] | E1 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | E01 |
| Danfoss AK-CC55 Water Loop[35] | E01 |
| Danfoss AK-CC 750[36] | System Critical exception |
| Danfoss EKC 202D1[41] | E1 |
| Danfoss EKC 326A[42] | E1 |
| Danfoss Optyma Plus[4] | A11 |
| Danfoss Optyma iCO2[46] | H23 |
| Danfoss Optyma iCO2[46] | H24 |
| Danfoss Optyma iCO2[46] | H25 |
| Danfoss Optyma iCO2[46] | H26 |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 4 |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 20 |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 24 |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | 30 |
| Copeland CoreSense Protection (Discus)[63] | LED red (steady) red steady |
| Copeland CoreSense Communications (13–15 ton scroll)[67] | LED red solid red steady |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED green 12 green ●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Danfoss CDS303/CDS803[69] | A38 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A38 |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A47 |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | DP 0X ADC Error |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | DP 0X CPU Error |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | DP 0X I/O Error |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | HLL |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | RL_Cal |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED red 7 red ●●●●●●● · 0.25 s on, 0.25 s off · pause 3 s |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED red 11 red ●●●●●●●●●●● · 0.25 s on, 0.25 s off · pause 3 s |
| Danfoss VLT FC 103[14] | W47 |
| NIBE F1255 ground source heat pump[78] | 427 |
| Secop SLV controller 105N46xx[81] | A96 |
| Secop SLV controller 105N46xx[81] | E90 |
| AHT electronic controller (plug-in cases, standard)[82] | FU6 |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | E70 |
| RDM DMTouch / miniDM[91] | Solid State Drive Read Only |
| RDM DMTouch / miniDM[91] | Disk warning |
| Störk-Tronic ST121 / ST501 / ST551[93] | EP0 |
| Kriwan INT69 PYF Diagnose[95] | LED red 5 / orange 1 red ●●●●● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 UY Diagnose[96] | LED red 3 / orange 3 red ●●● → orange ●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 YF Diagnose[98] | LED red 5 / orange 1 red ●●●●● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Fb |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | eCAL |
| Full Gauge TC-900E Log[118] | eCAL |
| Full Gauge MT-512E Log[121] | eCAL |
| Full Gauge MT-514E Faston[122] | eCAL |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | 16 |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | 17 |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A16 |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A19 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Ft |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | Ft |
| RDM Mercury AC and roof top unit controllers[130] | Ft |
| RDM ML Controller case controller[134] | Ft |
| Temperzone UC7 unit controller[101] | F29 |
| Danfoss ETC (True cabinets)[142] | E6 |
| Danfoss EETa (True cabinets, LED blink codes)[143] | 2+2 flashes |
| Taylor 736 soft serve freezer[153] | MICRO TA |
| Taylor 736 soft serve freezer[153] | DEV. KO |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er50 |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er57 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er50 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er51 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er56 |
| Taylor R200 fry dispenser[157] | Internal Issue |
| Taylor R280 fry dispenser[158] | Err 10 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | S.575 |
| Danfoss AK-PC 781A[37] | LED Status constantly onController software error. (The manual does not give the colour.) Symbol: green steady |
| Danfoss AK-PC 781A[37] | LED Status constantly offController software error (no status flashing). (The manual does not give the colour.) Symbol: green off (dark) |
| Copeland Digital Compressor Controller[61] | All LEDs on solid togetherDigital Compressor Controller has failed. Symbol: green steady |
| Copeland compressor electronics communications (20–40 ton scroll)[65] | LED red solidModule has an internal fault; cycle T2-T1 power, replace module if it persists. Alarm symbol: red steady |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | Reset LED flashingController is in a fault condition and is resetting. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red lit / yellow dark / green blinkPFC current sensing circuit fault. Alarm symbol: red ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red dark / yellow dark / green blinkCompressor current sensing circuit fault. Alarm symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red dark / yellow blink / green litCompressor IPM temperature sensor circuit fault. Alarm symbol: yellow ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red lit / yellow dark / green litEEPROM read error. Alarm symbol: red + green steady |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | D501 (red) flashing every 0.5 sNo EEPROM or EEPROM write failed. Symbol: red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | D502 (orange) not flashing after power-onIndoor P.C. board not working; check or replace it. Symbol: orange ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | D02 flashing 1 Hz for about 10 s, then rebootEEPROM missing or unreadable; unit loops through auto-address mode (F29/97). (The manual does not give the colour.) Symbol: red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Danfoss AK-PC 782A/782B[38] | LED Status constantly onController software fault. (The manual does not give the colour.) Symbol: green steady |
| Danfoss AK-PC 782A/782B[38] | LED Status constantly offController software fault (or no supply). (The manual does not give the colour.) Symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Kriwan INT69 F Diagnose[94] | LED red flashing (Temp. and Leak)Both Temp. and Leak LEDs flash red: internal error, the protection relay is defective. Alarm symbol: red ● · 0.35 s on, 0.35 s off |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | Controller FAULT LED red steadyController device fault: no application loaded. Alarm symbol: red steady |
| Taylor C392/C393/C394 frozen beverage freezers[150] | Universal Control LED green steady or offThe control board processor has stopped; the touchscreen shows "Communications with control board failed". Symbol: green steady |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | OPERATION lamp green flashing 5 HzA protective circuit has operated on a P.C. board (the table lists indoor and outdoor board); read the check code with the remote controller. Alarm symbol: green flashing fast |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D800+D801+D802 yellow (3 s on / 0.5 s off)Current error: Position detection circuit error (16). Alarm symbol: yellow ● → yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D803 yellow (3 s on / 0.5 s off)Current error: Current detection circuit error (17). Alarm symbol: yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | PCB LED D02 flashing 1 sNo EEPROM or EEPROM write fault. Alarm symbol: red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | Outdoor 7-segment HELLO over 1 minPossible interface board fault; power off for 30 s and restart. (The manual does not give the colour.) Alarm symbol: red steady |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Main board LED D1 green fast flashingHardware or firmware error. Alarm symbol: green flashing fast |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Keyboard LED D5 green 4 flashes per secondFlash memory or crystal problem; replace the board. Alarm symbol: green flashing fast |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Echelon LED red service steadyEchelon board has lost its program; replace the board. Alarm symbol: red steady |
| Danfoss AK-CC 750[36] | LED Status constantly onSoftware/controller error. (The manual does not give the colour.) Symbol: green steady |
| Danfoss AK-CC 750[36] | LED Status constantly offSoftware/controller error (no status flash). (The manual does not give the colour.) Symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp A 12 flashesFb indoor control board error (memory etc.) (wireless: count flashes after self-check; pattern A = indoor unit, starts after about 2.5 s off). Alarm symbol: green ●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | Light block Operation + Timer synchronized blinking, Ready offIndoor EEPROM fault (F29). (both blink together; Ready off.) (The manual does not give the colour.) Alarm symbol: green ● → yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | Light block Operation + Timer synchronized blinking, Ready onOutdoor EEPROM fault (F31). (both blink together; Ready lit.) (The manual does not give the colour.) Alarm symbol: green ● → yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| RDM Intuitive Superpack / Transcritical Superpack[132] | Reset LED flashingController is in a fault condition and is resetting. (The manual does not give the colour.) Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault R-on G-blinkPFC current-sensing circuit fault (red on, yellow off, green blink). Alarm symbol: red ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault G-blinkCompressor current-sensing circuit fault (red off, yellow off, green blink). Alarm symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault Y-blink G-onCompressor IPM temperature-sensor circuit fault (red off, yellow blink, green on). Alarm symbol: yellow ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault R-on G-onEEPROM read error (red on, yellow off, green on). Alarm symbol: red + green steady |
| IVT AirX air-to-water heat pump[175] | 5395Internal fault in the compressor inverter; often a loose CAN or Modbus connection, otherwise the inverter or the compressor itself. |
| IVT AirX air-to-water heat pump[175] | 5394Internal inverter fault (warning), often a loose CAN or Modbus connection. |
| IVT AirX air-to-water heat pump[175] | 5452Internal fault in the compressor inverter. |
| IVT AirX air-to-water heat pump[175] | 5523Internal fault 3 in the compressor inverter, usually temporary (on Geo models the same number is PFC overcurrent). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 251System fault in the base controller electronics. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5394Internal inverter fault (warning), often a loose CAN or Modbus connection. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5452Internal fault in the compressor inverter. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5523Internal fault 3 in the compressor inverter, usually temporary (on Geo models the same number is PFC overcurrent). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5524Internal fault 3 in the compressor inverter (alarm); on Geo models the same number is PFC overcurrent. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5646Fault in the inverter temperature sensor, LG code 65 (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5647Fault in the inverter temperature sensor, LG code 65 (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 258System fault in the base controller electronics; clears after a restart. |
| IVT Geo 500/600 series ground source heat pump[177] | 5394Internal inverter fault 1, usually temporary (warning). |
| IVT Geo 500/600 series ground source heat pump[177] | 5395Internal inverter fault (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5452Internal fault in the compressor inverter. |
| IVT Geo 500/600 series ground source heat pump[177] | 5904Fault in the compressor inverter. |
| IVT Geo 500/600 series ground source heat pump[177] | 5908The inverter control failed to initialise. |
| IVT Geo 500/600 series ground source heat pump[177] | 5988Fault in the inverter control MCE. |
| IVT Geo 312/412 ground source heat pump[178] | 5394Internal inverter fault 1, usually temporary (warning). |
| IVT Geo 312/412 ground source heat pump[178] | 5395Internal inverter fault (alarm). |
| IVT Geo 312/412 ground source heat pump[178] | 5452Internal fault in the compressor inverter. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5394Internal inverter fault (warning), often a loose CAN or Modbus connection. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5452Internal fault in the compressor inverter. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5523Internal fault 3 in the compressor inverter, usually temporary (on Geo models the same number is PFC overcurrent). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5524Internal fault 3 in the compressor inverter (alarm); on Geo models the same number is PFC overcurrent. |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 4 + Timer 2The manual/auto (forced) button has been held in for 30 s or more: check that it is not stuck, otherwise the indoor PCB is faulty. red + green ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 4 + Timer 7The electrostatic air cleaner protection has operated several times: check that the front panel is closed and the panel micro switch works. red + green ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 4 + Timer 8The air cleaner power circuit reports operation although air cleaning is off: air cleaner unit or indoor PCB faulty. red + green ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 5 + Timer 3Current sensor (CT) reads 0 A about one minute after the compressor started (code 18): check the CT wiring, then the PCB. red + green ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 4 + Timer 2Manual/auto button on the indoor unit reports a fault (20). green + orange ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 4 + Timer 7Electrostatic air cleaner filter fault (21). green + orange ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 4 + Timer 8Air cleaner power circuit fault on the indoor PCB (22). green + orange ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 5 + Timer 3Current sensor (CT) fault (18). green + orange ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 11Model information or indoor memory (EEPROM) fault on newer models; outdoor PCB failure in the older UK guide. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 18Current sensor (CT) fault: no current measured after the compressor started. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 20Manual/auto switch on the indoor unit abnormal. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 21Electrostatic air cleaner fault. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 22Air cleaner power circuit on the indoor PCB abnormal. |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | E:14Outdoor PCB failure. |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation blinking + Timer blinkingIndoor PCB failure. green + red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation blinking + Timer blinking + Swing blinkingOutdoor PCB failure. green + red + yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation blinking + Timer 11Current sensor (CT) fault. green + red ●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wall-mounted multi indoor units (older, UK; two-stage lamp code)[186] | Red 4 + Green blinking, test button: Red blinking + Green 2Indoor control fault group; after the test button: manual/auto button fault. red + green ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 9–30 (older, one red LED)[187] | LED red 11Current sensor (CT) fault. red ●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 9–30 (older, one red LED)[187] | LED red 14Timer (PCB) failure. red ●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu non-inverter outdoor unit PCB (older, two red LEDs)[189] | LED 1 blinking + LED 2 blinkingOutdoor PCB failure. red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter multi outdoor unit AOY30 (older, LEDs A–D)[190] | LED A–D 17 flashesOutdoor PCB fault. red ●●●●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red + Green short pulsesPCB failure. red + green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | 03The PCB has found an internal CPU fault in its self-check; nothing on the unit itself needs checking, so reset the power and replace the PCB if the code returns. |
| Fujitsu AIRSTAGE J-II VRF – wired and simple remote controllers UTY-RNK*, UTY-RSK*, UTY-RHK* (error code on the display)[197] | 32Indoor unit main PCB error (model information or EEPROM cannot be read). Switch off and on again; if it returns, replace the indoor controller PCB and set the address again. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 32Indoor unit main PCB error (model information or EEPROM). Reset the power, then replace the indoor controller PCB. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 62Outdoor main PCB error: EEPROM access (E.62.3), inverter communication (E.62.6) or corrupted setting data (E.62.8). See the outdoor display for the detail code. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 63Inverter error reported by the inverter PCB (E.63.1). Check the filter PCB to inverter PCB wiring, then the inverter PCB. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 77Heat sink thermistor inside the IPM faulty (E.77.1). Replace the inverter PCB. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 84Current sensor error on the filter PCB (E.84.1). Check the filter PCB to inverter PCB wiring. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | C4Group remote controller PCB error: its EEPROM cannot be written or a control port does not work; Operation LED flashes. Reset the power; if it returns, replace the group RC. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | CANetwork convertor software error (program, EEPROM or initial setting). Hold SW104 on the convertor for 5 s or switch off and on; if it returns, remove noise sources, then replace the convertor. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.63.1Inverter error reported by the inverter PCB. Check the filter PCB to inverter PCB wiring and connectors, then the inverter and filter PCBs. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.77.1Heat sink temperature sensor built into the IPM open or short. Replace the inverter PCB. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.84.1Current sensor error (sensor on the inverter filter PCB): 0 A read while the inverter runs at 20 rps or more for 1 min (twice), or full-scale while stopped. Check the filter PCB to inverter PCB sensor and supply wiring, then the filter and inverter PCBs. |
| Fujitsu AIRSTAGE J-II VRF – network convertor UTY-VGGX (group remote or single split connection)[202] | CASoftware error: program, EEPROM or initial setting of the convertor PCB failed. If it does not clear by itself, hold SW104 for 5 s or reset the power; if it returns, remove noise, then replace the convertor. |
| Fujitsu AIRSTAGE J-II VRF – indoor units (Operation/Timer/Filter lamps)[199] | Operation 3 + Timer 2 + Filter flashing fastIndoor unit main PCB error (code 32): model information or EEPROM cannot be read. The Filter lamp flickers fast (0.1 s) as the error marker; Operation and Timer flash their counts in turn. (The manual does not give the colour.) green + orange + red ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
The controller has detected an internal fault.
Check: Switch off the supply for a while and restart. If the fault remains, replace the controller and transfer the settings.
Configuration missing or wrong
| Controller | Code |
|---|---|
| Danfoss AK-CC 550 / 550B[33] | A11 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | A11 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | a04 |
| Danfoss AK-CC55 Water Loop[35] | a04 |
| Danfoss EIM 365[40] | No Rfg. Sel. |
| Danfoss EKE 1A/1B/1C/1D[43] | E101 |
| Danfoss EKE 1A/1B/1C/1D[43] | E011 |
| Danfoss EKE 1A/1B/1C/1D[43] | E103 |
| Danfoss EKE 100[44] | A03 |
| Danfoss EKE 100[44] | A11 |
| Danfoss EKE 100[44] | A12 |
| Copeland CoreSense Communications (13–15 ton scroll)[67] | LED green 4 green ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED blue 2 blue ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED blue 3 blue ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Danfoss Gas Sensor DGS[71] | Wrong type |
| Danfoss Gas Sensor DGS[71] | ? |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | ? |
| LG Multi V 5 VRF outdoor units[77] | CH51 |
| Secop SLV controller 105N46xx[81] | A76 |
| Secop SLV controller 105N46xx[81] | A91 |
| AHT GD-Cooler (GD-XLS, GD-XL)[84] | noL |
| Temperzone UC7 unit controller[101] | F26 |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 7100 |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 7102 |
| Goodman DX20VC inverter condensing unit[105] | E11 |
| Evco EV3 CHILL / HPRU (chiller, heat pump)[111] | ACnf |
| Hitachi multi-split heat pump[113] | 31 |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | PPPP |
| Full Gauge TC-900E Log[118] | PPPP |
| Full Gauge TC-940R[119] | PPP |
| Full Gauge MT-512E 2HP[120] | PPPP |
| Full Gauge MT-512E Log[121] | PPPP |
| Full Gauge MT-514E Faston[122] | PPPP |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | E08 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | L08 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | E08 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | L10 |
| RDM Intuitive / Mercury pack and condenser controllers[131] | Conf |
| RDM Intuitive / Mercury pack and condenser controllers[131] | Boot |
| RDM Intuitive / Mercury pack and condenser controllers[131] | Ctrl |
| RDM Intuitive Superpack / Transcritical Superpack[132] | Err |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | Modbus Addr Clash |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | Modbus Ctrl Source |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 73 |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 12 |
| Temperzone UC7 unit controller[101] | F27 |
| Temperzone UC7 unit controller[101] | F36 |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | non |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | SYn |
| Taylor R200 fry dispenser[157] | NV Data Bad |
| Taylor R280 fry dispenser[158] | Err 9 |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | SF |
| HTPG EcoNet enabled unit coolers[162] | A500 |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red lit / yellow dark / green darkDIP switch signal level abnormal. Alarm symbol: red steady |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red lit / yellow lit / green litCompressor model code from main controller does not match the drive EEPROM. Alarm symbol: red + yellow + green steady |
| Taylor R200 fry dispenser[157] | Load size LED does not stay litCalibration lost (or keypad fault): reset parameters to default and recalibrate. (The manual does not give the colour.) Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Display FH 0PAP mode activated but no Wi-Fi kit is fitted. (The manual does not give the colour.) Communication lamp: white steady |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D800+D802+D803+D804 yellow (3 s on / 0.5 s off)Current error: Miswiring (mispiping) check error. Alarm symbol: yellow ● → yellow ● → yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Carel EVD evolution / EVD evolution twin[16] | LED POWER green flashing + red alarm LEDDC supply used while the power-supply-mode parameter is set to AC; correct the parameter. Power lamp: green ● → red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Danfoss EKE 100[44] | Valve LED red+green flashing togetherValve type has not been defined; set the valve type. Symbol: red + green flashing fast |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | Light block Operation + Ready synchronized blinking, Timer offIndoor group/address/capacity setting error (L03, L05–L09). (both blink together; Timer off.) (The manual does not give the colour.) Alarm symbol: green ● → orange ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | Light block Operation + Ready synchronized blinking, Timer onOutdoor address/capacity/model setting error, or external interlock (L04, L10–L30). (both blink together; Timer lit.) (The manual does not give the colour.) Alarm symbol: green ● → orange ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | Light block Operation on, Timer + Ready alternate blinkingSetting incompatibility: auto cool/heat or heating selected on a model that cannot do it. (Operation lit.) (The manual does not give the colour.) Alarm symbol: yellow ● → orange ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault R-onDIP-switch signal level abnormal (red on, yellow off, green off). Alarm symbol: red steady |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault R-on Y-on G-onCompressor model code from the main controller does not match the drive EEPROM (red on, yellow on, green on). Alarm symbol: red + yellow + green steady |
| IVT AirX air-to-water heat pump[175] | 1081The room unit has the wrong address, so the system sees two master controllers. |
| IVT AirX air-to-water heat pump[175] | 1051A heating circuit is set to use the external room sensor module, but the module is not installed (one code per circuit, 4 min delay). |
| IVT AirX air-to-water heat pump[175] | 1052A heating circuit is set to use the external room sensor module, but the module is not installed (one code per circuit, 4 min delay). |
| IVT AirX air-to-water heat pump[175] | 1053A heating circuit is set to use the external room sensor module, but the module is not installed (one code per circuit, 4 min delay). |
| IVT AirX air-to-water heat pump[175] | 1054A heating circuit is set to use the external room sensor module, but the module is not installed (one code per circuit, 4 min delay). |
| IVT AirX air-to-water heat pump[175] | 1082The room unit for heating circuit 2 is wrongly set up as master controller (CO/SC). |
| IVT AirX air-to-water heat pump[175] | 1083The room unit for heating circuit 3 is wrongly set up as master controller (CO/SC). |
| IVT AirX air-to-water heat pump[175] | 1084The room unit for heating circuit 4 is wrongly set up as master controller (CO/SC). |
| IVT AirX air-to-water heat pump[175] | 3081The room unit refers to a heating circuit that does not exist. |
| IVT AirX air-to-water heat pump[175] | 3111A different room unit type (with or without humidity sensor) is connected than the one registered. |
| IVT AirX air-to-water heat pump[175] | 5522The indoor and outdoor units are not a valid combination. |
| IVT AirX air-to-water heat pump[175] | 6060The solar collector sensor is used as the sensor for a third solar tank. |
| IVT AirX air-to-water heat pump[175] | 6070The solar heating system has not been commissioned yet. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 1051A heating circuit is set to use the external room sensor module, but the module is not installed (one code per circuit, 4 min delay). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 1052A heating circuit is set to use the external room sensor module, but the module is not installed (one code per circuit, 4 min delay). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 1053A heating circuit is set to use the external room sensor module, but the module is not installed (one code per circuit, 4 min delay). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 1054A heating circuit is set to use the external room sensor module, but the module is not installed (one code per circuit, 4 min delay). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 1081The room unit for heating circuit 1 is wrongly set up as master controller (CO/SC). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 1082The room unit for heating circuit 2 is wrongly set up as master controller (CO/SC). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 1083The room unit for heating circuit 3 is wrongly set up as master controller (CO/SC). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 1084The room unit for heating circuit 4 is wrongly set up as master controller (CO/SC). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3081The room unit refers to a heating circuit that does not exist. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3111A different room unit type (with or without humidity sensor) is connected than the one registered. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5522The indoor and outdoor units are not a valid combination. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 6060The solar collector sensor is used as the sensor for a third solar tank. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 6070The solar heating system has not been commissioned yet. |
| IVT Geo 500/600 series ground source heat pump[177] | 1051Heating circuit 1 is set to use the external room sensor module, but the module is not installed (4 min delay). |
| IVT Geo 500/600 series ground source heat pump[177] | 1052Heating circuit 2 is set to use the external room sensor module, but the module is not installed (4 min delay). |
| IVT Geo 500/600 series ground source heat pump[177] | 1053Heating circuit 3 is set to use the external room sensor module, but the module is not installed (4 min delay). |
| IVT Geo 500/600 series ground source heat pump[177] | 1054Heating circuit 4 is set to use the external room sensor module, but the module is not installed (4 min delay). |
| IVT Geo 500/600 series ground source heat pump[177] | 1081The room unit for heating circuit 1 is wrongly set up as master controller. |
| IVT Geo 500/600 series ground source heat pump[177] | 1082The room unit for heating circuit 2 is wrongly set up as master controller. |
| IVT Geo 500/600 series ground source heat pump[177] | 1083The room unit for heating circuit 3 is wrongly set up as master controller. |
| IVT Geo 500/600 series ground source heat pump[177] | 1084The room unit for heating circuit 4 is wrongly set up as master controller. |
| IVT Geo 500/600 series ground source heat pump[177] | 3081A room unit is set to control heating circuit 1, which is not defined. |
| IVT Geo 500/600 series ground source heat pump[177] | 3082A room unit is set to control heating circuit 2, which is not defined. |
| IVT Geo 500/600 series ground source heat pump[177] | 3083A room unit is set to control heating circuit 3, which is not defined. |
| IVT Geo 500/600 series ground source heat pump[177] | 3084A room unit is set to control heating circuit 4, which is not defined. |
| IVT Geo 500/600 series ground source heat pump[177] | 3111A different room unit type (with or without humidity sensor) is connected than the one registered. |
| IVT Geo 500/600 series ground source heat pump[177] | 5522The heat pump and the indoor unit are not a valid combination. |
| IVT Geo 500/600 series ground source heat pump[177] | 5909A circulation pump with unknown functions is connected to the Modbus. |
| IVT Geo 312/412 ground source heat pump[178] | 1051Heating circuit 1 is set to use the external room sensor module, but the module is not installed (4 min delay). |
| IVT Geo 312/412 ground source heat pump[178] | 1052Heating circuit 2 is set to use the external room sensor module, but the module is not installed (4 min delay). |
| IVT Geo 312/412 ground source heat pump[178] | 1053Heating circuit 3 is set to use the external room sensor module, but the module is not installed (4 min delay). |
| IVT Geo 312/412 ground source heat pump[178] | 1054Heating circuit 4 is set to use the external room sensor module, but the module is not installed (4 min delay). |
| IVT Geo 312/412 ground source heat pump[178] | 1081The room unit for heating circuit 1 is wrongly set up as master controller. |
| IVT Geo 312/412 ground source heat pump[178] | 1082The room unit for heating circuit 2 is wrongly set up as master controller. |
| IVT Geo 312/412 ground source heat pump[178] | 1083The room unit for heating circuit 3 is wrongly set up as master controller. |
| IVT Geo 312/412 ground source heat pump[178] | 1084The room unit for heating circuit 4 is wrongly set up as master controller. |
| IVT Geo 312/412 ground source heat pump[178] | 3111A different room unit type (with or without humidity sensor) is connected than the one registered. |
| IVT Geo 312/412 ground source heat pump[178] | 5522The heat pump and the indoor unit are not a valid combination. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 1051A heating circuit is set to use the external room sensor module, but the module is not installed (one code per circuit, 4 min delay). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 1052A heating circuit is set to use the external room sensor module, but the module is not installed (one code per circuit, 4 min delay). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 1053A heating circuit is set to use the external room sensor module, but the module is not installed (one code per circuit, 4 min delay). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 1054A heating circuit is set to use the external room sensor module, but the module is not installed (one code per circuit, 4 min delay). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 1081The room unit for heating circuit 1 is wrongly set up as master controller (CO/SC). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 1082The room unit for heating circuit 2 is wrongly set up as master controller (CO/SC). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 1083The room unit for heating circuit 3 is wrongly set up as master controller (CO/SC). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 1084The room unit for heating circuit 4 is wrongly set up as master controller (CO/SC). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3081The room unit refers to a heating circuit that does not exist. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3111A different room unit type (with or without humidity sensor) is connected than the one registered. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5522The indoor and outdoor units are not a valid combination. |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 5 + Timer 7Model information mismatch or connected indoor unit error read from memory (code 1F); often a PCB fault or a wrong replacement PCB. red + green ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 5 + Timer 7The outdoor unit does not accept the connected indoor unit (1F): check models and capacity combination. green + orange ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 11 flashesTotal capacity of the connected indoor units is not accepted. red ●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 21 flashesModel information on the outdoor PCB is wrong or unreadable. red ●●●●●●●●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 1FConnected indoor unit or model information not accepted. |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | E:11Model abnormal: indoor and outdoor PCB do not match. |
| Fujitsu wall-mounted multi indoor units (older, UK; two-stage lamp code)[186] | Red blinking + Green 4, test button: Red 2 + Green blinkingIndoor units wrongly connected; after the test button: wrong indoor unit index (piping and wiring do not match). red + green ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter multi outdoor unit AOY30 (older, LEDs A–D)[190] | LED A–D 11 flashesIndoor unit indexing problem: piping and wiring of the circuits do not match. red ●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | 31No capacity is set for the unit: check that DSW1 on the PCB matches the model (4–10 HP); change DIP switches only with the power off. |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | ddThe room thermostat is wired wrongly: check the wiring to PCB terminals A, D, E and F against the wiring label. |
| Fujitsu AIRSTAGE J-II VRF – wired and simple remote controllers UTY-RNK*, UTY-RSK*, UTY-RHK* (error code on the display)[197] | 15Scan error / incompatible indoor unit: the RC gets no unit information. Check the master/slave setting (one RC = master; two RCs = one master, one slave; RC plus external switch controller = RC master), the cable and indoor power, then the RC and the indoor PCB. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | --Initial setting error: DIP switch settings on the outdoor main PCB were wrong at power-on (see outdoor display ----). Correct them and switch on again. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 15System error: units were registered within 4 min of power-on, the registration spans 3 or more refrigerant systems, only a slave unit or a non-existing unit is registered, or the outdoor unit is not in the same circuit. Correct the registration and the indoor DIP/rotary switches. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 26Address setting error: no indoor unit is registered in the group RC. Register the indoor units again in function setting mode (hold TIME< and TIME>). Operation LED flashes. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 28Other setting error: auto addressing of indoor units (outdoor E.28.1) or of signal amplifiers (E.28.4) failed. See the outdoor codes. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | ----Initial setting error (flashing 0.5 s on/off): a DIP switch on the outdoor main PCB was set wrongly at power-on; indoor units show nothing. Check the master/address switches (for the master unit SET3-1 and SET3-2 off), correct and switch on again. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.28.1Auto address setting error: no indoor unit answered, or an abnormal answer came, during auto addressing. Check indoor power, that no more than 64 indoor units are on one refrigerant circuit, the communication line terminals and noise or power cuts during addressing. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.28.4Signal amplifier auto address error. Check the amplifier power, that no more than 8 amplifiers are in the network, and that auto addressing was not started from more than one master outdoor unit at the same time. |
| Fujitsu AIRSTAGE J-II VRF – signal amplifier UTY-VSGX (7-segment display)[201] | 26Address setting error: no address set in the signal amplifier; no operation. Reset with SW7 or power; if it remains, set the address again and reset the power, then replace the amplifier. |
| Fujitsu AIRSTAGE J-II VRF – network convertor UTY-VGGX (group remote or single split connection)[202] | 26Group RC use: indoor units of 3 or more refrigerant circuits are registered on one convertor (reduce to 2 or fewer and wait 2 min). Single split use: communication error with the indoor unit (same checks as 16). |
The controller has not been set up completely (for example no refrigerant chosen) or the inputs and outputs are assigned in a way it cannot use, so control does not start.
Check: Go through the start-up settings: refrigerant, connection/application number and the input/output assignment, then start control with the main switch.
Clock, battery or memory fault
| Controller | Code |
|---|---|
| Carel EVD evolution / EVD evolution twin[16] | EEPROM damaged |
| Carel EVD ice / EVD mini[17] | EE |
| Carel Heos[18] | tC |
| Carel ir33 universale[19] | E06 |
| Carel ir33 universale[19] | E07 |
| Carel ir33 universale[19] | E08 |
| Carel ir33+ VCC[20] | Etc |
| Carel ir33+ VCC[20] | EE |
| Carel ir33+ VCC[20] | EF |
| Carel MPXone[21] | Etc |
| Carel pRack pR300[22] | ALG01 |
| Carel SmartCella / SmartCella 3PH[24] | Etc |
| Carel SmartCella / SmartCella 3PH[24] | EE |
| Carel SmartCella / SmartCella 3PH[24] | EF |
| Carel µRack[25] | EPb |
| Copeland EazyCool ZX (XCM25D)[5] | E86 |
| Copeland Large ZX 22–30 HP[29] | L86 |
| Danfoss AK-CC 450[32] | E6 |
| Danfoss AK-CC 550 / 550B[33] | E6 |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | E06 |
| Danfoss AK-CC55 Water Loop[35] | E06 |
| Danfoss AK-CC 750[36] | Clock has not been set |
| Danfoss Optyma control AK-RC 113[39] | E2 |
| Danfoss EKC 202D1[41] | E6 |
| Danfoss EKE 100[44] | A07 |
| Danfoss EKC 202A/B/C[2] | E6 |
| Dixell XEV12D[49] | EE |
| Dixell XM669K/XM679K[50] | rtC |
| Dixell XM669K/XM679K[50] | rtF |
| Dixell XM669K/XM679K[50] | EE |
| Dixell XR460C[53] | EE |
| Dixell XR460C[53] | rtc |
| Dixell XR460C[53] | rtF |
| Dixell XR70CX[54] | rtc |
| Dixell XR70CX[54] | rtF |
| Dixell XW60K/XW60L[55] | EE |
| Dixell XW60K/XW60L[55] | rtc |
| Dixell XW60K/XW60L[55] | rtF |
| Dixell XWi70K[56] | EE |
| Carel µC2SE for process chiller[59] | EPb |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | DP 0X EE Error |
| AHT electronic controller (plug-in cases, standard)[82] | Clock |
| AHT electronic controller (plug-in cases, standard)[82] | EE |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | A90 |
| Pego ECP200 EXPERT PULSE[89] | EE |
| Pego ECP200 EXPERT PULSE[89] | E6 |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | E2 |
| Störk-Tronic ST121 / ST501 / ST551[93] | EP1 |
| Störk-Tronic ST121 / ST501 / ST551[93] | EP2 |
| Störk-Tronic ST121 / ST501 / ST551[93] | rtc |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | FC |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | LED red 2 + pause red ●● · 0.25 s on, 0.25 s off · pause 2 s |
| Evco EVK214[109] | rtc |
| Full Gauge TC-900E Log[118] | adfL |
| Full Gauge TC-900E Log[118] | emem |
| Full Gauge TC-900E Log[118] | eCLO |
| Full Gauge MT-512E Log[121] | adfL |
| Full Gauge MT-512E Log[121] | emem |
| Full Gauge MT-512E Log[121] | eCLO |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | F31 |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A13 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | EH 00 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | EC 51 |
| ActronAir Nexus Touch Controller WTC-01[139] | E0 |
| Dixell XR/XW (True cabinets)[145] | EE |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | CONFIG CRC ERR |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er15 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er15 |
| Taylor R200 fry dispenser[157] | NV Data Lost |
| Carel MPXzero (Hillphoenix display cases)[160] | Etc |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | Etc |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | CE |
| HTPG EcoNet enabled unit coolers[162] | A502 |
| HTPG EcoNet enabled unit coolers[162] | A503 |
| LAE BR1-27/BR1-28/BR5-A/BR5-B/BD1-28/CD25[165] | TIM |
| Pego 202BASE electronic board[167] | E2 |
| BAC Nexus modular hybrid cooler (NXF controls)[172] | Al_retain |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Running lamp 1, timer offIndoor unit EEPROM parameter error (EH 00 / EH 0A). (The manual does not give the colour.) Alarm symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33[11] | Icon clock flashingReal-time clock alarm. (The manual does not give the colour.) Clock symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| IVT AirX air-to-water heat pump[175] | 1038Time and date have not been set. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 1038Time and date have not been set. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5638Faulty EEPROM on the outdoor unit circuit board, LG code 60 (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5639Faulty EEPROM on the outdoor unit circuit board, LG code 60 (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 1038Time and date have not been set. |
| IVT Geo 312/412 ground source heat pump[178] | 1038Time and date have not been set. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 1038Time and date have not been set. |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | All lamps blinkingIndoor unit memory (EEPROM) or model information cannot be read (code 11); the UK guide calls it an indoor PCB failure. red + green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | All four lamps blinkingIndoor unit memory (EEPROM) cannot be read (wired code 11): indoor PCB fault. green + orange + blue + yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.62.3Outdoor unit EEPROM access error on the main PCB. Reset the power; if it returns, replace the main PCB and set the original address. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.62.8EEPROM data corrupted: the checksum of the field (F2) settings does not match. Clear all field settings with F3-35 and set the F2 settings again; if it returns, replace the main PCB. |
| Carel MasterCella[7] | Clock icon flashingClock alarm. (The manual does not give the colour.) Clock symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33+ VCC[20] | Clock icon flashing (Etc)The real-time clock is faulty. (The manual does not give the colour.) Clock symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
The real-time clock, its battery or the parameter memory (EEPROM) is faulty or has lost its data.
Check: Set the clock, replace the battery if fitted, and check the parameters; replace the controller if the memory fault returns.
Power backup module or battery fault
| Controller | Code |
|---|---|
| Danfoss EKE 1A/1B/1C/1D[43] | A997 |
| Danfoss EKE 1A/1B/1C/1D[43] | A984 |
| Danfoss EKE 1A/1B/1C/1D[43] | A985 |
| Danfoss EKE 100[44] | A01 |
| Danfoss EKE 100[44] | A02 |
| Carel µC2SE for process chiller[59] | Eb1 |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | UPS Error |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Battery icon yellowLess than 30 % of battery life left. Power lamp: yellow steady |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Battery icon redLess than 10 % battery life left, or the battery enable switch is off. Power lamp: red steady |
| Carel EVD evolution / EVD evolution twin[16] | LED alarm red flashingBackup battery discharged, faulty or disconnected. Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| NIBE F1255 ground source heat pump[78] | SMS 40 LED BATT offSMS 40 battery is discharged or not fitted. (The manual does not give the colour.) Power lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
The battery or backup module that should close the electronic valve at a power cut is low, faulty or due for replacement, so the valve may stay open if the supply fails.
Check: Measure the backup voltage, check its wiring and replace the backup module or battery; until then there is a risk of liquid flooding at a power failure.
Communication fault
| Controller | Code |
|---|---|
| Carel MPX[6] | MA |
| Zanotti GM/GS[10] | E7 |
| Carel ir33[11] | n1-n6 |
| Danfoss VLT FC 103[14] | A17 |
| Danfoss VLT FC 103[14] | A34 |
| Carel EVD evolution / EVD evolution twin[16] | LAN error |
| Carel EVD evolution / EVD evolution twin[16] | Display connection error |
| Carel EVD ice / EVD mini[17] | E6 |
| Carel Heos[18] | MA |
| Carel ir33+ VCC[20] | COM |
| Carel MPXone[21] | MA |
| Carel MPXone[21] | u1...u9 |
| Carel pRack pR300[22] | ALO02 |
| Carel pRack pR300T (transcritical CO2)[23] | ALO02 |
| Carel SmartCella / SmartCella 3PH[24] | n1-n6 |
| Copeland EXD-SH1/2[26] | ACEr |
| Heatcraft Beacon II[30] | E9 |
| Heatcraft Beacon II[30] | +COMM+ |
| Danfoss AK-CC 750[36] | IO module error |
| Danfoss AK-CC 750[36] | Alarm route failure |
| Danfoss AK-PC 781A[37] | Common IO Alarm |
| Danfoss AK-PC 782A/782B[38] | Common IO Alarm |
| Danfoss Optyma iCO2[46] | E90 |
| Dixell XM669K/XM679K[50] | noL |
| Dixell XWi70K[56] | noL |
| Carel µC2SE for process chiller[59] | I/O |
| Carel µC2SE for process chiller[59] | Ed1 |
| Carel µChiller[60] | A41 |
| Copeland PerformanceAlert diagnostic module[62] | 10 flashes yellow ●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Protection (Discus)[63] | LED green 5 green ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland compressor electronics communications (20–40 ton scroll)[65] | LED green 1 green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Communications (13–15 ton scroll)[67] | LED green 1 green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED green 10 green ●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Danfoss VLT HVAC Basic Drive FC 101[70] | A17 |
| Danfoss Gas Sensor DGS[71] | Comm. err. |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | DP 0X Error |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | SB 0X Error |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | EP_06 0X Error |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | Comm. err. |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | SKF |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | No Comms |
| ebm-papst EC fans via Modbus (ECCN gateway, CN1116 MDC)[73] | D/C |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED red 4 red ●●●● · 0.25 s on, 0.25 s off · pause 3 s |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | U4 |
| LG Multi V 5 VRF outdoor units[77] | CH53 |
| AHT electronic controller (plug-in cases, standard)[82] | Bus |
| AHT electronic controller (plug-in cases, standard)[82] | Col |
| AHT electronic controller (plug-in cases, standard)[82] | FU1 |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | Err |
| RDM DMTouch / miniDM[91] | Offline |
| RDM DMTouch / miniDM[91] | Dial out failed |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | 6607 |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | E8 |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | E9 |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | E6 |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | E7 |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | E9 |
| Goodman DX20VC inverter condensing unit[105] | E51 |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | LED green/red 1 s green + red ● · 1 s on, 1 s off |
| Evco EV3 CHILL / HPRU (chiller, heat pump)[111] | ACoM |
| Evco EV3 MVC / EVD MVC (air handling)[112] | AL04 |
| Hitachi multi-split heat pump[113] | 03 |
| Hitachi multi-split heat pump[113] | 04 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | E04 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | E06 |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | E31 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | E03 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | E04 |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | E18 |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | A28 |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | Brd |
| RDM Intuitive Superpack / Transcritical Superpack[132] | br 1–br 10 |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | Modbus Dev OffLine |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | 1 |
| Temperzone UC8 unit controller[100] | F22 |
| Temperzone UC8 unit controller[100] | F39 |
| Temperzone UC7 unit controller[101] | F21 |
| Temperzone UC7 unit controller[101] | F22 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E15 |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | E51 |
| ActronAir Aires and Advance 19–25 kW[137] | E15 |
| ActronAir Aires and Advance 19–25 kW[137] | E51 |
| ActronAir Aires and Advance 19–25 kW[137] | E52 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | EL 01 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | EH 0b |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | EL 11 |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | PC 40 |
| ActronAir Nexus Touch Controller WTC-01[139] | FA |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | EoC |
| Danfoss ETC (True cabinets)[142] | E13 |
| True Ice TI/TCIM ice machines[147] | COM |
| Taylor 736 soft serve freezer[153] | COM. KO |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er52 |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er58 |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | Er61 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er52 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er58 |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Er61 |
| Carel MPXzero (Hillphoenix display cases)[160] | E11 |
| Carel MPXzero (Hillphoenix display cases)[160] | E12 |
| Carel MPXzero (Hillphoenix display cases)[160] | E13 |
| Carel MPXzero (Hillphoenix display cases)[160] | E14 |
| Carel MPXzero (Hillphoenix display cases)[160] | MA |
| Carel MPXzero (Hillphoenix display cases)[160] | u1...u9 |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | COM |
| HTPG EcoNet enabled unit coolers[162] | A005 |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Device Absent From Network |
| Krack KR-A2L unit cooler (KE2 Evap leak sensor alarms)[164] | LC1 |
| Krack KR-A2L unit cooler (KE2 Evap leak sensor alarms)[164] | LC2 |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | S.581 |
| Vaillant aroSTOR plus VWL B/BM 200/6, 260/6[171] | E08 |
| BAC Nexus modular hybrid cooler (NXF controls)[172] | Al_Offline_EBM_n |
| BAC Nexus modular hybrid cooler (NXF controls)[172] | Al_CommunicationErr_EBM_n |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | 20 flashes |
| Danfoss AK-PC 781A[37] | LED Comm redCommunication error with the bottom PC board/internal modules. Communication lamp: red steady |
| Danfoss AK-PC 781A[37] | LED Comm quick flashInternal communication error between modules. (The manual does not give the colour.) Communication lamp: red flashing fast |
| Danfoss AK-PC 781A[37] | Extension module LED comm redExtension module has lost communication with the controller. Communication lamp: red steady |
| LG Multi V 5 VRF outdoor units[77] | Communication LED (yellow) offNo internal PCB communication; check cables, fuses and PCBs. Communication lamp: yellow ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| LG Multi V 5 VRF outdoor units[77] | Heat recovery unit LED (green) on continuouslyHeat recovery unit PCB not communicating; check indoor communication or replace PCB. Communication lamp: green steady |
| LG Multi V 5 VRF outdoor units[77] | 485 modem LED red onHeat recovery (2A) communication fault; reset outdoor and heat recovery unit power. Communication lamp: red steady |
| LG Multi V 5 VRF outdoor units[77] | 485 modem LED red flashing485 modem fault; replace the modem (then the heat recovery PCB if it persists). Communication lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Goodman DX20VC inverter condensing unit[105] | Red communications LED 1 flashCommunications failure or unknown packet received; check wiring, press LEARN. Communication lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Goodman DX20VC inverter condensing unit[105] | Green receive LED offNo power to the unit, open fuse or communication error. Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Goodman DX20VC inverter condensing unit[105] | Green receive LED 1 steady flashNo network found: broken communication wire or unit wired as legacy system. Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Goodman DX20VC inverter condensing unit[105] | Green receive LED on solidTerminal 1/2 miswired, reversed or shorted (to each other or to 24 V C/R). Communication lamp: green steady |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | LED on-line (green) flashingTrying to log on to the network, or the unit has gone off-line/lost its address. Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red dark / yellow blink / green blinkNo or invalid data from the main controller to the drive for 30 s. Alarm symbol: yellow ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | Fan LED red 20xModbus communication error. Fan symbol: red ●●●●●●●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Running lamp 2, timer offIndoor/outdoor communication error (EL 01). (The manual does not give the colour.) Alarm symbol: green ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Running lamp 9, timer offCommunication error between indoor PCB and display board (EH 0b). (The manual does not give the colour.) Alarm symbol: green ●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Running lamp 6 + timer flashingCommunication error between outdoor main chip and compressor drive chip (PC 40). (The manual does not give the colour.) Alarm symbol: green ●●●●●● → orange ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | Display Err1The display cannot load data from the controller; unplug and reconnect the display. (The manual does not give the colour.) Communication lamp: red steady |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | Display Err2Communication between display and controller is lost. (The manual does not give the colour.) Communication lamp: red steady |
| Danfoss AK-PC 782A/782B[38] | LED Comm quick flashInternal communication fault between the controller and its bottom board or modules. Communication lamp: red flashing fast |
| Danfoss AK-PC 782A/782B[38] | LED Comm constantly onInternal communication fault between the controller and its bottom board or modules. Communication lamp: red steady |
| Danfoss AK-PC 782A/782B[38] | Module LED comm redThe extension module has lost communication with the controller. Communication lamp: red steady |
| BAC TrilliumSeries adiabatic cooler TRF[174] | HMI fan dot grayFan status Offline: the fan has not answered within 150 ms. Fan symbol: white steady |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | Controller bus LED green steadySA bus, FC bus or Modbus LED lit steady: communication lost, waiting to rejoin the bus. Communication lamp: green steady |
| NIBE F1255 ground source heat pump[78] | Inverter status LED red flashingOpen circuit on terminal block X4 of the inverter. Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss Optyma iCO2[46] | Display F0-F99No communication between the display and the unit controller. Communication lamp: green steady |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D800+D803 yellow (3 s on / 0.5 s off)Current error: Communication error between MCUs (1C). Alarm symbol: yellow ● → yellow ● · 3 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Dixell XM669K/XM679K[50] | Board LED green blinkingThe LAN connection is wrongly configured. Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XM669K/XM679K[50] | Board LED green offThe LAN is not working (also check this when rPF is shown). Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XM669K/XM679K[50] | Display nodThe keyboard is trying to work with a board that is missing or not working; select LOC in the SEC menu. (The manual does not give the colour.) Communication lamp: red steady |
| Copeland CoreSense Protection (Discus)[63] | LED red steady after RS485 wiringRS485 polarity is wrong (Pos and Neg swapped); correct polarity makes the red and green LEDs flash. Communication lamp: red steady |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | 6 flashesIndoor-outdoor serial communication failed for 3 min (E8/E9). (The manual does not give the colour.) Communication lamp: red ●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Echelon LED red reset onEchelon port is held in reset (a short flash means it has just reset). Communication lamp: red steady |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Echelon LED red service flashingNode has no subnet/node address; reset the E2, then replace the board if it persists. Communication lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel EVD evolution / EVD evolution twin[16] | LED NET green offNo network connection (LAN connection error); control falls back to DI1/DI2. Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel EVD evolution / EVD evolution twin[16] | LED NET green flashingNetwork communication error with the pCO/supervisor. Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-CC 750[36] | LED Comm redInternal communication with the lower circuit board has failed. Communication lamp: red steady |
| Danfoss AK-CC 750[36] | LED Comm quick flashInternal communication between the modules is faulty. (The manual does not give the colour.) Communication lamp: green flashing fast |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp A 3 flashesE6/E7 indoor–outdoor communication error (wireless: count flashes after self-check; pattern A = indoor unit, starts after about 2.5 s off). Alarm symbol: green ●●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp A 7 flashesEE indoor–outdoor communication error (wireless: count flashes after self-check; pattern A = indoor unit, starts after about 2.5 s off). Alarm symbol: green ●●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp A 9 flashesE4/E5 remote controller signal receiving error (wireless: count flashes after self-check; pattern A = indoor unit, starts after about 2.5 s off). Alarm symbol: green ●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp B 1 flashE9 indoor–outdoor communication (transmitting) error at the outdoor unit (pattern B = outdoor/other unit: lamp on for about 3 s, then the flashes). Alarm symbol: green ● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Outdoor board LED1 2 blinks, LED2 1 blinkWrong indoor–outdoor wiring (S1, S2, S3 polarity) or short in the remote controller wire. (The manual does not give the colour.) Communication lamp: red ●● → red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | Light block Operation blinkingRemote/receiving-unit or indoor-unit communication or address fault (E01–E03, E08–E12, E18). (Timer and Ready off.) (The manual does not give the colour.) Alarm symbol: green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | Light block Ready blinkingIndoor–outdoor or outdoor–outdoor communication/address fault (E04, E06, E07, E15–E31). (Operation and Timer off.) (The manual does not give the colour.) Alarm symbol: orange ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD fault Y-blink G-blinkNo or invalid data from the main controller for 30 s (red off, yellow blink, green blink). Alarm symbol: yellow ● → green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| IVT AirX air-to-water heat pump[175] | 1010Communication on the EMS bus has been lost. |
| IVT AirX air-to-water heat pump[175] | 3071No EMS communication with the room unit (one code per heating circuit); check the cable and keep it away from mains cables. |
| IVT AirX air-to-water heat pump[175] | 1001No communication between the controller and the room unit, probably a loose connection. |
| IVT AirX air-to-water heat pump[175] | 3061No EMS communication with the mixing module for heating circuit 1 for 4 minutes; clears itself when it returns. |
| IVT AirX air-to-water heat pump[175] | 3062No EMS communication with the mixing module for heating circuit 2 for 4 minutes; clears itself when it returns. |
| IVT AirX air-to-water heat pump[175] | 3063No EMS communication with the mixing module for heating circuit 3 for 4 minutes; clears itself when it returns. |
| IVT AirX air-to-water heat pump[175] | 3064No EMS communication with the mixing module for heating circuit 4 for 4 minutes; clears itself when it returns. |
| IVT AirX air-to-water heat pump[175] | 5265The heat pump circuit board does not answer on the CAN bus between heat pump and indoor unit (warning). |
| IVT AirX air-to-water heat pump[175] | 5266CAN bus to the heat pump board lost three times within 3 h or for 15 min (alarm). |
| IVT AirX air-to-water heat pump[175] | 5330No communication with the compressor inverter: no supply to the outdoor unit or a wrongly routed CAN cable between indoor and outdoor unit (warning). |
| IVT AirX air-to-water heat pump[175] | 5331No communication with the compressor inverter (alarm); also check the earth connection between inverter and compressor. |
| IVT AirX air-to-water heat pump[175] | 5503Connection to the load (power) monitor lost, usually temporary (warning). |
| IVT AirX air-to-water heat pump[175] | 5504Connection to the load monitor lost three times within 3 h or for 30 min (alarm). |
| IVT AirX air-to-water heat pump[175] | 5541No communication with the pool module. |
| IVT AirX air-to-water heat pump[175] | 5593The pool module has not answered for 90 s or more. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 1001No communication between the controller and the room unit, probably a loose connection. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 1010Communication on the EMS bus has been lost. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3061No EMS communication with the mixing module for heating circuit 1 for 4 minutes; clears itself when it returns. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3062No EMS communication with the mixing module for heating circuit 2 for 4 minutes; clears itself when it returns. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3063No EMS communication with the mixing module for heating circuit 3 for 4 minutes; clears itself when it returns. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3064No EMS communication with the mixing module for heating circuit 4 for 4 minutes; clears itself when it returns. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3071No EMS communication with the room unit (one code per heating circuit); check the cable and keep it away from mains cables. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3072No EMS communication with the room unit (one code per heating circuit); check the cable and keep it away from mains cables. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3073No EMS communication with the room unit (one code per heating circuit); check the cable and keep it away from mains cables. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3074No EMS communication with the room unit (one code per heating circuit); check the cable and keep it away from mains cables. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5265The heat pump circuit board does not answer on the CAN bus between heat pump and indoor unit (warning). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5266CAN bus to the heat pump board lost three times within 3 h or for 15 min (alarm). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5330No communication with the compressor inverter: no supply to the outdoor unit or a wrongly routed CAN cable between indoor and outdoor unit (warning). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5331No communication with the compressor inverter (alarm); also check the earth connection between inverter and compressor. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5503Connection to the load (power) monitor lost, usually temporary (warning). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5504Connection to the load monitor lost three times within 3 h or for 30 min (alarm). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5541No communication with the pool module. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5593The pool module has not answered for 90 s or more. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5632Internal communication fault in the inverter, LG code 52. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5634Internal CAN communication fault in the outdoor unit, LG code 53 (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5635Internal CAN communication fault in the outdoor unit, LG code 53 (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 1001No communication between the controller and the room unit, probably a loose connection. |
| IVT Geo 500/600 series ground source heat pump[177] | 1010Communication on the EMS bus lost, temporarily or by a broken connection. |
| IVT Geo 500/600 series ground source heat pump[177] | 3061No EMS communication with the mixing module for heating circuit 1. |
| IVT Geo 500/600 series ground source heat pump[177] | 3062No EMS communication with the mixing module for heating circuit 2. |
| IVT Geo 500/600 series ground source heat pump[177] | 3063No EMS communication with the mixing module for heating circuit 3. |
| IVT Geo 500/600 series ground source heat pump[177] | 3064No EMS communication with the mixing module for heating circuit 4. |
| IVT Geo 500/600 series ground source heat pump[177] | 3071No EMS communication with the room unit (one code per heating circuit); check the cable and keep it away from mains cables. |
| IVT Geo 500/600 series ground source heat pump[177] | 3072No EMS communication with the room unit (one code per heating circuit); check the cable and keep it away from mains cables. |
| IVT Geo 500/600 series ground source heat pump[177] | 3073No EMS communication with the room unit (one code per heating circuit); check the cable and keep it away from mains cables. |
| IVT Geo 500/600 series ground source heat pump[177] | 3074No EMS communication with the room unit (one code per heating circuit); check the cable and keep it away from mains cables. |
| IVT Geo 500/600 series ground source heat pump[177] | 3181The wireless room sensor for heating circuit 1 sends no signal, usually too far from its receiver. |
| IVT Geo 500/600 series ground source heat pump[177] | 5265The heat pump circuit board does not answer (warning). |
| IVT Geo 500/600 series ground source heat pump[177] | 5266The heat pump circuit board is not connected (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5330No communication with the compressor inverter, no supply to its I/O (warning). |
| IVT Geo 500/600 series ground source heat pump[177] | 5331No communication with the compressor inverter, no supply to its I/O (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5503Problem with the connection to the load monitor, usually temporary (warning). |
| IVT Geo 500/600 series ground source heat pump[177] | 5504Connection to the load monitor lost (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5541Communication with the pool board failed. |
| IVT Geo 500/600 series ground source heat pump[177] | 5593No communication with the pool module, usually temporary. |
| IVT Geo 500/600 series ground source heat pump[177] | 5993No communication between the inverter control and the main controller. |
| IVT Geo 312/412 ground source heat pump[178] | 1001No communication between the controller and the room unit, probably a loose connection. |
| IVT Geo 312/412 ground source heat pump[178] | 1010Communication on the EMS bus lost, temporarily or by a broken connection. |
| IVT Geo 312/412 ground source heat pump[178] | 3061No EMS communication with the mixing module for heating circuit 1. |
| IVT Geo 312/412 ground source heat pump[178] | 3062No EMS communication with the mixing module for heating circuit 2. |
| IVT Geo 312/412 ground source heat pump[178] | 3063No EMS communication with the mixing module for heating circuit 3. |
| IVT Geo 312/412 ground source heat pump[178] | 3064No EMS communication with the mixing module for heating circuit 4. |
| IVT Geo 312/412 ground source heat pump[178] | 3071No EMS communication with the room unit (one code per heating circuit); check the cable and keep it away from mains cables. |
| IVT Geo 312/412 ground source heat pump[178] | 3072No EMS communication with the room unit (one code per heating circuit); check the cable and keep it away from mains cables. |
| IVT Geo 312/412 ground source heat pump[178] | 3073No EMS communication with the room unit (one code per heating circuit); check the cable and keep it away from mains cables. |
| IVT Geo 312/412 ground source heat pump[178] | 3074No EMS communication with the room unit (one code per heating circuit); check the cable and keep it away from mains cables. |
| IVT Geo 312/412 ground source heat pump[178] | 5265The heat pump circuit board does not answer (warning). |
| IVT Geo 312/412 ground source heat pump[178] | 5266The heat pump circuit board is not connected (alarm). |
| IVT Geo 312/412 ground source heat pump[178] | 5330No communication with the compressor inverter, no supply to its I/O (warning). |
| IVT Geo 312/412 ground source heat pump[178] | 5331No communication with the compressor inverter, no supply to its I/O (alarm). |
| IVT Geo 312/412 ground source heat pump[178] | 5503Problem with the connection to the load monitor, usually temporary (warning). |
| IVT Geo 312/412 ground source heat pump[178] | 5504Connection to the load monitor lost (alarm). |
| IVT Geo 312/412 ground source heat pump[178] | 5541Communication with the pool board failed. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 1001No communication between the controller and the room unit, probably a loose connection. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 1010Communication on the EMS bus has been lost. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3061No EMS communication with the mixing module for heating circuit 1 for 4 minutes; clears itself when it returns. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3062No EMS communication with the mixing module for heating circuit 2 for 4 minutes; clears itself when it returns. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3063No EMS communication with the mixing module for heating circuit 3 for 4 minutes; clears itself when it returns. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3064No EMS communication with the mixing module for heating circuit 4 for 4 minutes; clears itself when it returns. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3071No EMS communication with the room unit (one code per heating circuit); check the cable and keep it away from mains cables. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3072No EMS communication with the room unit (one code per heating circuit); check the cable and keep it away from mains cables. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3073No EMS communication with the room unit (one code per heating circuit); check the cable and keep it away from mains cables. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3074No EMS communication with the room unit (one code per heating circuit); check the cable and keep it away from mains cables. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5265The heat pump circuit board does not answer on the CAN bus between heat pump and indoor unit (warning). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5266CAN bus to the heat pump board lost three times within 3 h or for 15 min (alarm). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5330No communication with the compressor inverter: no supply to the outdoor unit or a wrongly routed CAN cable between indoor and outdoor unit (warning). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5331No communication with the compressor inverter (alarm); also check the earth connection between inverter and compressor. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5503Connection to the load (power) monitor lost, usually temporary (warning). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5504Connection to the load monitor lost three times within 3 h or for 30 min (alarm). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5541No communication with the pool module. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5593The pool module has not answered for 90 s or more. |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation off + Timer 2Indoor and outdoor unit could not talk to each other at start-up (reverse transfer, wired remote code 01): check the interconnecting cable and the voltage at indoor and outdoor unit. green ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation off + Timer 3Indoor and outdoor unit lost contact for about 10 s during operation (reverse transfer): check the interconnecting cable, splices and supply voltage. green ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation off + Timer 4No forward signal from the outdoor unit at start-up (wired remote code 13): reset the power, then check the cable and voltages. green ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation off + Timer 5Forward signal from the outdoor unit lost during operation (wired remote code 13): check the cable, splices and supply. green ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation off + Timer 8The indoor unit and the wired remote do not communicate (code 00): check the remote cable and the 12 V DC at the indoor connector; with voltage present the remote is faulty. green ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Timer 2Reverse transfer error at start-up between indoor and outdoor unit (wired code 01). orange ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Timer 3Reverse transfer error during operation between indoor and outdoor unit. orange ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Timer 4Forward transfer signal from the outdoor unit missing at start-up (wired code 13). orange ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Timer 8Wired remote and indoor unit do not communicate (wired code 00). orange ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 5 + Timer 8Main CPU and sub CPU on the outdoor PCB do not communicate (1C). green + orange ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 1 flashNo forward signal between the outdoor unit and indoor unit A. red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 2 1 flashNo forward signal between the outdoor unit and indoor unit B. red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 3 1 flashNo forward signal between the outdoor unit and indoor unit C. red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 4 1 flashNo forward signal between the outdoor unit and indoor unit D. red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 17 flashesMicrocomputers on the outdoor PCB do not communicate. red ●●●●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 00Indoor unit and wired remote do not communicate: check the remote cable (screened, away from mains cables) and the 12 V DC at the indoor unit. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 01Indoor and outdoor unit do not communicate (reverse transfer): check the interconnecting cable, crimped joints and supply voltage. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 13Forward signal from the outdoor unit missing or abnormal. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 1CCommunication fault between the inverter and the main outdoor PCB (main/sub CPU). |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 26Indoor signal error. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 27Indoor signal error. |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | E0:00Indoor unit and wired remote do not communicate; check the remote cable and interference. |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | E1:00Indoor and outdoor unit do not communicate; check the interconnecting cable. |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | E:13Signal from the outdoor unit abnormal. |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation 5 + Timer blinkingIndoor and outdoor unit do not communicate. green + red ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation 5 + Timer blinking + Swing blinkingOutdoor PCB or interconnecting wiring fault. green + red + yellow ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wall-mounted multi indoor units (older, UK; two-stage lamp code)[186] | Red 5 + Green blinking, test button: Red blinking + Green 2Communication fault group; after the test button: reverse transfer (indoor to outdoor) fault. red + green ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wall-mounted multi indoor units (older, UK; two-stage lamp code)[186] | Red 5 + Green blinking, test button: Red blinking + Green 3Communication fault group; after the test button: forward transfer (outdoor to indoor) fault. red + green ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 9–30 (older, one red LED)[187] | LED red 1Communication fault with the indoor unit. red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 9–30 (older, one red LED)[187] | LED red 9Indoor communication error. red ●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 36–54 (older, one red LED)[188] | LED red 1Communication fault with the indoor unit. red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Fujitsu non-inverter outdoor unit PCB (older, two red LEDs)[189] | LED 1 5 + LED 2 steadyCommunication fault with the indoor unit. red ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter multi outdoor unit AOY30 (older, LEDs A–D)[190] | LED A–D 1 flashesCommunication fault with the indoor unit on this circuit. red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red 5 short + Green rapid (F)Communication failure between indoor and outdoor unit. red + green ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu AIRSTAGE J-II VRF – wired and simple remote controllers UTY-RNK*, UTY-RSK*, UTY-RHK* (error code on the display)[197] | 12Remote controller lost contact with its indoor unit: the indoor unit sent no signal for over 1 min. Check the RC cable and the indoor power, that RC addresses run from 0 without gaps, then measure about 12 V DC at the RC connector on the indoor PCB (12 V: replace the RC; 0 V: replace the indoor PCB). |
| Fujitsu AIRSTAGE J-II VRF – wired and simple remote controllers UTY-RNK*, UTY-RSK*, UTY-RHK* (error code on the display)[197] | 14Network communication error: the indoor unit has heard nothing from the outdoor unit for about 90 s. If only some indoor units show it, check their communication PCB and wiring; if all do, check the outdoor communication PCB and the network line. |
| Fujitsu AIRSTAGE J-II VRF – wired and simple remote controllers UTY-RNK*, UTY-RSK*, UTY-RHK* (error code on the display)[197] | 16Indoor unit parallel communication error between the indoor controller PCB and its communication PCB. Check that the communication PCB is fitted and plugged in, then replace it, then the controller PCB. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 12Remote controller communication error (with the indoor unit or the network convertor). On a convertor no valid signal has arrived for 90 s: check the convertor power, the RC line and voltage dips or noise; then the RC. Operation LED flashes. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 14Network or transmission error: the signal from a registered indoor unit (not a slave) has been lost for over 10 min, or the outdoor unit lost an indoor unit. Check the transmission cable and the indoor and convertor power. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 16Indoor unit parallel communication error (indoor controller PCB to communication PCB). Check and replace the indoor communication PCB. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 69Outdoor unit transmission PCB parallel communication error (E.69.1). Check the outdoor communication PCB and its connector. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | C1Network convertor PCB error 1: synchronisation with the network device failed. Hold SW104 for 5 s or reset the power; if it returns, remove noise sources, then replace the convertor. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.14.1Network communication error 1: an indoor unit that has communicated before has been silent for 180 s or more. Check that indoor unit’s power, the network line, the terminal resistor setting, noise and its communication PCB. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.14.2Network communication error 2: all indoor units have been silent for 180 s or more (indoor units show 9/15). Check the network line from the outdoor unit, the terminal resistor, the indoor power and the outdoor communication PCB. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.14.5Indoor unit shortage: fewer indoor units than the stored maximum have answered for 180 s after power-on. The system keeps running. Find the missing unit (power, line, terminal resistor, communication PCB); afterwards clear the stored count with function F3-41. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.62.6Inverter communication error: no signal from the inverter PCB for 10 s or more. Check the main–inverter PCB cable, then the inverter PCB and main PCB. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.69.1Outdoor transmission PCB parallel communication error (failed 5 times). Check that the outdoor communication PCB is seated and connected; then replace it. |
| Fujitsu AIRSTAGE J-II VRF – signal amplifier UTY-VSGX (7-segment display)[201] | C1Parallel communication error between the CPU and the network driver IC. Press RESET (SW7) or switch off and on; if it comes back, remove noise sources, then replace the amplifier. |
| Fujitsu AIRSTAGE J-II VRF – signal amplifier UTY-VSGX (7-segment display)[201] | D9Communication error B (CH_B side network driver IC), display flashing or steady; no operation. Reset with SW7; if it returns, remove noise, then replace the amplifier. |
| Fujitsu AIRSTAGE J-II VRF – signal amplifier UTY-VSGX (7-segment display)[201] | D14Communication error A (CH_A side network driver IC), display flashing or steady; no operation. Reset with SW7; if it returns, remove noise, then replace the amplifier. |
| Fujitsu AIRSTAGE J-II VRF – network convertor UTY-VGGX (group remote or single split connection)[202] | C1PCB error 1: synchronisation with the network device failed; nothing can be controlled. Hold SW104 for 5 s or switch off and on; if it comes back, remove noise sources, then replace the convertor. |
| Fujitsu AIRSTAGE J-II VRF – network convertor UTY-VGGX (group remote or single split connection)[202] | 12Communication error with the connected (group or standard) remote controller; control from that RC is not possible. Check the RC cable and terminals, DIP-SW103 1–4 on (group RC) or DIP-SW107-2 wired RC enable (single split), the RC’s DIP switch for the number of RCs, then the RC or convertor. |
| Fujitsu AIRSTAGE J-II VRF – network convertor UTY-VGGX (group remote or single split connection)[202] | 16Communication error with the single split indoor unit; nothing operates. Check the RC cable to the indoor unit, indoor power, the indoor main unit address, and DIP-SW103 1–8 (indoor type, RC type, number of units), then the indoor PCB or convertor. |
| Fujitsu AIRSTAGE J-II VRF – indoor units (Operation/Timer/Filter lamps)[199] | Operation 1 + Timer 2 + Filter flashing fastRemote controller communication error (RC code 12). Check the RC cable, RC addresses and 12 V DC at the RC connector on the indoor PCB. The Filter lamp flickers fast (0.1 s) as the error marker; Operation and Timer flash their counts in turn. (The manual does not give the colour.) green + orange + red ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu AIRSTAGE J-II VRF – indoor units (Operation/Timer/Filter lamps)[199] | Operation 1 + Timer 4 + Filter flashing fastNetwork communication error (code 14): no signal from the outdoor unit for about 90 s. Check the network line and the communication PCBs. The Filter lamp flickers fast (0.1 s) as the error marker; Operation and Timer flash their counts in turn. (The manual does not give the colour.) green + orange + red ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu AIRSTAGE J-II VRF – indoor units (Operation/Timer/Filter lamps)[199] | Operation 1 + Timer 6 + Filter flashing fastIndoor unit parallel communication error (code 16) between the controller PCB and the communication PCB. The Filter lamp flickers fast (0.1 s) as the error marker; Operation and Timer flash their counts in turn. (The manual does not give the colour.) green + orange + red ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu AIRSTAGE J-II VRF – external switch controller UTY-TEKX (LED)[203] | LED flashing 0.5 s on / 0.5 s offUTY-TEKX: remote controller cable abnormal, no communication with the indoor unit for over 1 min. Check the cable, DIP-SW1-4/1-5/1-6 and noise. (The manual does not give the colour.) green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Fujitsu AIRSTAGE J-II VRF – external switch controller UTY-TEKX (LED)[203] | LED flashing 0.5 s on / 1.0 s offUTY-TEKX: transmission error, normal communication with the indoor unit suspended for over 1 min. Check DIP-SW1-4/1-5/1-6 and noise. (The manual does not give the colour.) green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Secop BD electronic units (BD35F/BD50F/BD35K/BD80CN, 101N0212/0340/0390/0420/0510/0650)[80] | 7 flashesCommunication error; the manual lists it as error code 7 and says the codes can also be read on the error LED. (The manual does not give the colour.) Symbol: red ●●●●●●● · 0.25 s on, 0.25 s off · pause 2 s |
| NIBE F1255 ground source heat pump[78] | MODBUS 40 LED COM2MODBUS 40: indicates no active communication with the external control system. (The manual does not give the colour.) Communication lamp: green steady |
| NIBE F1255 ground source heat pump[78] | SMS 40 LED LEV offSMS 40 GSM signal is too weak. (The manual does not give the colour.) Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
The connection between parts of the controller (display and power board, or master and slave) is broken.
Check: Check cables and connectors between the units and restart them.
Service or maintenance reminder
| Controller | Code |
|---|---|
| Carel pRack pR300[22] | ALT01 |
| Carel µRack[25] | A05 |
| Dixell XC645D[48] | A14 |
| Carel µC2SE for process chiller[59] | Hc1 |
| Danfoss Gas Sensor DGS[71] | LED green flashing green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss Gas Sensor DGS[71] | Calibration due |
| Danfoss Gas Sensor DGS[71] | # |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | Maintenance |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | # |
| Evco EV3 CHILL / HPRU (chiller, heat pump)[111] | AHou |
| Thermia Calibra[115] | Class B |
| Thermia Calibra[115] | Class C |
| Full Gauge TC-900E Log[118] | AMai |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | BRUSH CLEAN TIMEOUT |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | BRUSH CLEAN TIMEOUT |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | SrC |
| LAE BR1-27/BR1-28/BR5-A/BR5-B/BD1-28/CD25[165] | CL |
| LAE AT1-5/AT2-5[166] | CL |
| alpha innotec BWP 190S/260S DHW heat pump[168] | Er10 |
| alpha innotec WWB 190 DHW heat pump[169] | E11 |
| Carel µRack[25] | Icon MANUFACTURER + ALARM flashingCompressor maintenance hours exceeded. (The manual does not give the colour.) Service symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM Mercury AC and roof top unit controllers[130] | LED service (spanner)The service interval (P-26 run hours) has expired; service the unit and reset the counter. (The manual does not give the colour.) Service symbol: red steady |
| RDM ML Controller case controller[134] | LED service (spanner)The service interval has expired; service the case and reset the interval parameter. (The manual does not give the colour.) Service symbol: red steady |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | Symbol maintenance (spanner)Maintenance is due or the unit runs in restricted (comfort protection) mode; it keeps running. (The manual does not give the colour.) Service symbol: white steady |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | Display Lhm.37Comfort protection: a permanent fault was detected and the unit runs with reduced comfort. (The manual does not give the colour.) Service symbol: white steady |
| True Ice TI/TCIM ice machines[147] | UV LED red steadyUV lamp operating time exceeded; replace the lamp. Service symbol: red steady |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | Brush-clean countdown shows 1Machine must be disassembled and brush-cleaned within 24 h. (The manual does not give the colour.) Service symbol: red steady |
| Carel µChiller[60] | Service (spanner) icon steadyA device has reached its programmed operating-hour threshold; maintenance is due (see the code). (The manual does not give the colour.) Service symbol: red steady |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | LED green flashingMaintenance (calibration/service) message is due. Service symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM Mercury 3 Twin Coil[92] | LED service (spanner) steadyService interval set in P-18 has elapsed; service is due. (The manual does not give the colour.) Service symbol: red steady |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | LED service (spanner) steadyRun-hours service interval (P-18) has elapsed; service is due. (The manual does not give the colour.) Service symbol: red steady |
| Carel MPXzero (Hillphoenix display cases)[160] | Service icon steadyMaintenance request. (The manual does not give the colour.) Service symbol: red steady |
| IVT AirX air-to-water heat pump[175] | 6219Reminder that the 3-year or 5-year warranty service is due. |
| IVT AirX air-to-water heat pump[175] | 6220The service reminder was acknowledged three times; only a technician can clear it. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 6219Warranty service reminder after 3 and 5 years of operation; shown together with 6220. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 6220Warranty service reminder after 3 and 5 years of operation; shown together with 6219. |
| IVT Geo 500/600 series ground source heat pump[177] | 6219Warranty service reminder after 3 and 5 years of operation; shown together with 6220. |
| IVT Geo 500/600 series ground source heat pump[177] | 6220Warranty service reminder after 3 and 5 years of operation; shown together with 6219. |
| IVT Geo 312/412 ground source heat pump[178] | 6219Reminder that the 3-year or 5-year warranty service is due. |
| IVT Geo 312/412 ground source heat pump[178] | 6220The service reminder was acknowledged three times; only a technician can clear it. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5596Reminder to clean the exhaust air filter, every 2 months; a low pressure warning (5666) also triggers it. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 6219Warranty service reminder after 3 and 5 years of operation; shown together with 6220. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 6220Warranty service reminder after 3 and 5 years of operation; shown together with 6219. |
| Fujitsu AIRSTAGE J-II VRF – indoor units (Operation/Timer/Filter lamps)[199] | Filter steadyFilter sign: time to clean the air filter; reset the filter sign after cleaning. (The manual does not give the colour.) Service symbol: red steady |
A run-hour or service interval has expired, or the controller asks for a check.
Check: Carry out the service and reset the counter according to the manual.
Status: normal operation
| Controller | Code |
|---|---|
| Copeland CoreSense Diagnostics (UltraTech scroll)[66] | LED green solidThe module has its 18-28 V supply and works normally; no trip is active. green steady |
| Copeland CoreSense Diagnostics (scroll AC)[64] | LED yellow (steady)The module is powered and the compressor/system runs normally. yellow steady |
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED green solidNormal compressor operation, no alert active. green steady |
| Copeland CoreSense Communications (13–15 ton scroll)[67] | LED green solidThe module is powered and operating normally. green steady |
| Copeland compressor electronics communications (20–40 ton scroll)[65] | LED green solidThe module is powered and operating normally. green steady |
| Copeland CoreSense Protection (Discus)[63] | LED green (steady)Normal state: the compressor is either running or normally off, with no warning, trip or lockout. green steady |
| Copeland Stream condensing units (Next Gen CoreSense)[27] | LED green steadyNormal operation; no faults on the compressor. green steady |
| Danfoss Optyma Plus Module B Plus (P02)[45] | LED2 green steadyStatus LED: Module B Plus is powered and has no error. green steady |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED greenNo warning and no fault; the fan is ready for operation. green steady |
| Danfoss Gas Sensor DGS[71] | LED green steadyPower on, no alarm and no fault. green steady |
| Heatcraft A2L Refrigerant Detection System (unit coolers)[79] | LED green steadyInitialization finished; the detection system is in normal operation. green steady |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | LED steadyThe inverter board LED stays lit during normal operation. red steady |
| Carel EVD ice / EVD mini[17] | Start/stop LED (decimal point) blinkingStart/stop digital input is closed and superheat control is active. (The manual does not give the colour.) Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-PC 781A[37] | LED Status slow flashSoftware running normally; controller ready (about one minute after power on). (The manual does not give the colour.) Symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-PC 781A[37] | LED Alarm offNo active and no unacknowledged alarms. (The manual does not give the colour.) Alarm symbol: red off (dark) |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | Extension module LED blue onLow-pressure transmitter input on the extension module is working correctly. Symbol: blue steady |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | Extension module LED red onHigh-pressure transmitter input on the extension module is working correctly (red here is not a fault). Symbol: red steady |
| Secop SLV controller 105N46xx[81] | External operating LED (DI1 = 18) onController is running (not in Stopped mode). (The manual does not give the colour.) Power lamp: green steady |
| LG Multi V 5 VRF outdoor units[77] | Main PCB 7-segment LED blank after power-onSelf-diagnostics (about 3 min) finished; unit ready for auto addressing. (The manual does not give the colour.) Power lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| LG Multi V 5 VRF outdoor units[77] | Communication LED (yellow) blinkingCommunication between main PCB, inverter compressor PCBs, fan PCB or MICOMs is normal. Communication lamp: yellow ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| LG Multi V 5 VRF outdoor units[77] | External PCB communication LED blinkingSignal between main PCB and external PCB is normal. (The manual does not give the colour.) Communication lamp: yellow ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| LG Multi V 5 VRF outdoor units[77] | Heat recovery unit LED (green) blinkingHeat recovery unit PCB is powered and communicating. Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Goodman DX20VC inverter condensing unit[105] | Red communications LED offNormal condition, no communication fault. Communication lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Goodman DX20VC inverter condensing unit[105] | Green receive LED rapid flashingNormal network traffic; the control is talking on the network. Communication lamp: green flashing fast |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | LED on-line (green) steadyConnected and on-line on the network. Communication lamp: green steady |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | Status LED 2 flashesController is working normally (two flashes at one-second intervals). (The manual does not give the colour.) Symbol: green ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | Status bar blueNormal operation, no alarm. Symbol: blue steady |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | Expansion module status LED flashingExpansion I/O module is powered and healthy. (The manual does not give the colour.) Power lamp: green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir Aires and Advance 19–25 kW[137] | Indoor board COM1/COM2 LEDs blinkingCommunication on the wall control/outdoor (or InZone) RS485 lines is occurring. (The manual does not give the colour.) Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Taylor 736 soft serve freezer[153] | Ice cream cone icon steadyProduct is within about 10 % of set consistency and ready to serve. (The manual does not give the colour.) Symbol: white steady |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | Fan LED solid redNormal fan operation (red is normal here). Fan symbol: red steady |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | D14 (orange) flashingIndoor PCB is receiving the serial signal from the outdoor unit. Communication lamp: orange ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | D15 (green) flashingIndoor PCB is sending the serial signal to the outdoor unit. Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| AHT electronic controller (plug-in cases, standard)[82] | Lamp 3 greenMechanical controller: the cabinet is in normal operation with no fault. Power lamp: green steady |
| AHT electronic controller (plug-in cases, standard)[82] | Lamp 3a greenMechanical controller: deep-freeze mode (-) selected and running normally. Power lamp: green steady |
| AHT electronic controller (plug-in cases, standard)[82] | Lamp 3b greenMechanical controller: cooling mode (+) selected and running normally. Power lamp: green steady |
| Danfoss AK-PC 782A/782B[38] | LED Status slow flashSoftware running normally; the controller is ready about a minute after power-on. (The manual does not give the colour.) Symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-PC 782A/782B[38] | LED Alarm offNo active and no unacknowledged alarms. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| BAC TrilliumSeries adiabatic cooler TRF[174] | EC fan LED greenEC fan motor: status good, ready for operation. Fan symbol: green steady |
| BAC TrilliumSeries adiabatic cooler TRF[174] | HMI fan dot greenFan status Good: no active fan alarms. Fan symbol: green steady |
| Heatcraft Beacon II[30] | Display oFFOff cycle: room temperature is satisfied, or the unit is switched off; alternates with the box temperature. Power lamp: red steady |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | Controller FAULT LED offNo controller faults. Alarm symbol: red ● · 1 s on, 1 s off |
| NIBE F1255 ground source heat pump[78] | Board LED Run green flashingThe card processor is working (about one flash per second). Symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| NIBE F1255 ground source heat pump[78] | Inverter status LED green steadyCompressor stopped, no fault. Compressor symbol: green steady |
| NIBE F1255 ground source heat pump[78] | Inverter status LED green flashingCompressor stopped, no fault. Compressor symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss Optyma iCO2[46] | Display S0Normal control. green steady |
| Danfoss Optyma iCO2[46] | Display S11Thermostat cut-out on DI2 (no cooling demand). green steady |
| Carel pRack pR300[22] | Terminal LED yellowThe pRack controller is switched on. Power lamp: yellow steady |
| Taylor C392/C393/C394 frozen beverage freezers[150] | Universal Control LED green blinkingHeartbeat: the control board processor is working. Symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LED D805 green on, D800-D804 offOutdoor P.C. board initial display: normal operation, no error. green steady |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | Symbol filling pressure steadyHeating circuit filling pressure is within the permitted range. (The manual does not give the colour.) Water symbol: white steady |
| Bitzer VARIPACK FMY+/FMU+ .. FSW+ (frequency inverter)[58] | Lamp P02Panel lamp in the wiring example: the compressor is ready to operate. (The manual does not give the colour.) Compressor symbol: green steady |
| Carel pRack pR300T (transcritical CO2)[23] | Terminal LED yellow steadyThe pRack unit is switched on. Power lamp: yellow steady |
| Danfoss Optyma control AK-RC 113[39] | Icon stand-by steadyPanel is on and regulating. (The manual does not give the colour.) Power lamp: red steady |
| Castel 5650E/5658E electronic oil level regulator (R744)[123] | LED OIL GOOD green steadyOil level is correct. Symbol: green steady |
| RDM Intuitive / Mercury pack and condenser controllers[131] | LED network steadyOn-line on the network. (The manual does not give the colour.) Communication lamp: green steady |
| Danfoss EETa (True cabinets, LED blink codes)[143] | LED flashing once per secondPower on, no alarm. (The manual does not give the colour.) Power lamp: green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| True Ice TI/TCIM ice machines[147] | UV LED blue steadyUV ballast is on and working correctly. Symbol: blue steady |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Main board LED D1 green flashing 1 s on/1 s offMain board is working normally. Power lamp: green ● · 1 s on, 1 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Keyboard LED D5 green flashing 1 s on/1 s offKeyboard status normal. Symbol: green ● · 1 s on, 1 s off · pause 2 s (timing assumed, not stated in the manual) |
| Danfoss AK-CC 750[36] | LED Status slow flashSoftware running normally; controller ready (about 1 minute after power-up). (The manual does not give the colour.) Symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss EKE 100[44] | LED alarm red offNo alarm or warning on valve A or B. Alarm symbol: red off (dark) |
| Danfoss EKE 100[44] | Valve LED red steadyValve (A or B) is fully closed. Symbol: red steady |
| Danfoss EKE 100[44] | Valve LED offValve is idle at its target position. Symbol: red off (dark) |
| Danfoss EKE 100[44] | Valve LED green steadyValve is fully open. Symbol: green steady |
| Temperzone UC8 unit controller[100] | Display dot flashingNormal operation (standby or running). (The manual does not give the colour.) Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Indoor board LED3 blinkingIndoor–outdoor communication is running (should always blink). (The manual does not give the colour.) Communication lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Outdoor board only LED1 lit after start-upNormal: both LEDs light at power-on, then LED2 goes out (about 2 minutes start-up). (The manual does not give the colour.) Power lamp: red steady |
| RDM Intuitive Superpack / Transcritical Superpack[132] | Status bar blue steadyNormal operation, no alarm. Symbol: blue steady |
| RDM Intuitive Superpack / Transcritical Superpack[132] | Status LED double flash every secondController is working normally. (The manual does not give the colour.) Symbol: green ●● · 0.5 s on, 0.5 s off · pause 1 s (timing assumed, not stated in the manual) |
| RDM Intuitive Superpack / Transcritical Superpack[132] | Expansion module status LED flashing 0.5 sExpansion I/O module is powered and healthy. (The manual does not give the colour.) Power lamp: green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Indoor board COM1 + COM2 LEDs blinkingIndoor board is communicating with the wall controller and outdoor unit; no blinking points to a communication fault. (The manual does not give the colour.) Communication lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Krack KR-A2L unit cooler (KE2 Evap leak sensor alarms)[164] | Danfoss sensor LED green (steady or blinking)Sensor is powered and in normal status. Power lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Krack KR-A2L unit cooler (KE2 Evap leak sensor alarms)[164] | Copeland sensor PWR green steady, red offNormal monitoring, no refrigerant detected. Power lamp: green steady |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation steadyUnit switched on, no fault. (The manual does not give the colour.) Power lamp: green steady |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red steadyUnit switched on and running normally. Power lamp: red steady |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | LED101 POWER/MODE steadyOutdoor main PCB has power; ERROR LED102 is off when there is no fault. Power lamp: green steady |
| Thermia Atella / Robust[114] | Alarm indicator green steadyNormal operation, no alarm. Alarm symbol: green steady |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | LED valve steady (Control Thermostat)On the Control Thermostat the valve LED shows the controller's operating state. (The manual does not give the colour.) Symbol: red steady |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Echelon LED red service offNormal operation: the Echelon service LED should be dark. Communication lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
The lamp shows that the unit has power and works normally; no fault is active.
Check: Nothing to do; if the unit still does not cool, troubleshoot the symptom (the controller sees no fault).
Status: running or demand
| Controller | Code |
|---|---|
| Copeland CoreSense Diagnostics (refrigeration scroll ZB/ZF/ZS)[68] | LED blue slow flashingDigital unloader solenoid is energized (scroll unloaded); the on period varies about 2-20 s with the capacity demand. blue ● · 2 s on, 2 s off (timing assumed, not stated in the manual) |
| Copeland Digital Compressor Controller[61] | UNLOADER LED yellow onThe digital unloader solenoid is energized, so the compressor is running unloaded at that moment. yellow steady |
| Kriwan INT69 F Diagnose[94] | LED green flashingNo fault; the machine is running. green ● · 0.35 s on, 0.35 s off |
| Kriwan INT69 PYF Diagnose[95] | LED green flashingNo fault; the machine is running. green ● · 0.35 s on, 0.35 s off |
| Kriwan INT69 YF Diagnose[98] | LED green flashingNo fault; the machine is running. green ● · 0.35 s on, 0.35 s off |
| Kriwan INT69 UY Diagnose[96] | LED green flashingNo fault; the machine is running. green ● · 0.35 s on, 0.35 s off |
| Kriwan INT69 Y Diagnose[97] | LED green flashingNo fault; the machine is running. green ● · 0.35 s on, 0.35 s off |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | LED green 1 sKB drive ST LED: normal operation, drive in run mode. green ● · 1 s on, 1 s off |
| Danfoss ERC 21X[1] | Icon compressor steadyCompressor output is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Danfoss ERC 21X[1] | Icon compressor flashingCompressor running in a pull-down cycle. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss ERC 21X[1] | Icon fan steadyEvaporator fan is running. (The manual does not give the colour.) Fan symbol: red steady |
| Copeland EazyCool ZX (XCM25D)[5] | LED compressor onCompressor 1 is enabled. (The manual does not give the colour.) Compressor symbol: red steady |
| Copeland EazyCool ZX (XCM25D)[5] | LED condenser fan onCondenser fans are enabled. (The manual does not give the colour.) Fan symbol: red steady |
| Copeland EazyCool ZX (XCM25D)[5] | LED digital unloader onDigital scroll unloader solenoid is energised (compressor unloaded). (The manual does not give the colour.) Compressor symbol: red steady |
| Copeland EazyCool ZX (XCM25D)[5] | LED evaporator fan / liquid solenoid onEvaporator fans or liquid-line solenoid valve output is on. (The manual does not give the colour.) Fan symbol: red steady |
| Carel MPXone[21] | Icon solenoid/compressor onSolenoid or compressor output is active (cooling request). (The manual does not give the colour.) Compressor symbol: red steady |
| Carel MPXone[21] | Icon evaporator fan onEvaporator fan is on. (The manual does not give the colour.) Fan symbol: red steady |
| Carel µRack[25] | Icon fan onAt least one condenser fan is running (or fan parameters being set). (The manual does not give the colour.) Fan symbol: red steady |
| Carel µRack[25] | Icon compressor onAt least one compressor step is active (or compressor parameters being set). (The manual does not give the colour.) Compressor symbol: red steady |
| Carel µRack[25] | Icons 1–4 (steps) onShows which compressors/capacity steps (or fans, in fan-only mode) are on. (The manual does not give the colour.) Compressor symbol: red steady |
| Copeland Large ZX 22–30 HP[29] | LED 1 onCompressor 1 is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Copeland Large ZX 22–30 HP[29] | LED 2 onCompressor 2 is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Copeland Large ZX 22–30 HP[29] | LED condenser fan onCondensing fan is running. (The manual does not give the colour.) Fan symbol: red steady |
| Copeland Large ZX 22–30 HP[29] | LED digital compressor onDigital compressor is unloading. (The manual does not give the colour.) Compressor symbol: red steady |
| Copeland Large ZX 22–30 HP[29] | LED liquid line solenoid onLiquid-line solenoid valve is energised. (The manual does not give the colour.) Symbol: red steady |
| Danfoss AK-CC 550 / 550B[33] | LED refrigeration onRefrigeration relay is on (cooling in progress). (The manual does not give the colour.) Compressor symbol: red steady |
| Danfoss AK-CC 550 / 550B[33] | LED fan onFan relay is on. (The manual does not give the colour.) Fan symbol: red steady |
| Danfoss AK-PC 781A[37] | LED DO1–DO8 onThe corresponding relay output is on. (The manual does not give the colour.) Symbol: green steady |
| Danfoss AK-PC 781A[37] | Stepper module LED step OPEN greenStepper valve output is driving open. Symbol: green steady |
| Danfoss AK-PC 781A[37] | Stepper module LED step CLOSE greenStepper valve output is driving closed. Symbol: green steady |
| Danfoss EKC 202D1[41] | LED refrigeration onRefrigeration (compressor/solenoid) relay is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Danfoss EKC 202D1[41] | LED fan onEvaporator fan is running. (The manual does not give the colour.) Fan symbol: red steady |
| Dixell XEV12D[49] | LED valve onExpansion valve is open. Symbol: red steady |
| Dixell XR460C[53] | Icon compressor 1 onCompressor 1 output is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XR460C[53] | Icon compressor 2 onCompressor 2 output is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XR460C[53] | Icon fan onEvaporator fan output is enabled. (The manual does not give the colour.) Fan symbol: red steady |
| Pego ECP200 EXPERT PULSE[89] | Icon EEV output onElectronic expansion valve output is on. (The manual does not give the colour.) Symbol: red steady |
| Pego ECP200 EXPERT PULSE[89] | Icon cold call (compressor) onCooling is called; compressor output is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Pego ECP200 EXPERT PULSE[89] | Icon fans onEvaporator fans are called on. (The manual does not give the colour.) Fan symbol: red steady |
| Secop SLV controller 105N46xx[81] | LED Cooling onCompressor cooling is active. (The manual does not give the colour.) Compressor symbol: red steady |
| Störk-Tronic ST121 / ST501 / ST551[93] | LED1 on (default)Compressor/solenoid valve output is on (default assignment U11 = 1; can be reassigned). This default applies to the ST121/ST501; on the ST551 LED1 shows an alarm by default. Compressor symbol: red steady |
| Störk-Tronic ST121 / ST501 / ST551[93] | LED3 on (default)Evaporator fan is on (default U13 = 3; can be reassigned). This default applies to the ST121/ST501; on the ST551 LED3 shows a low-pressure alarm by default. Fan symbol: red steady |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | LED compressor onCompressor output is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | LED compressor flashing fastFast freezing mode is running (compressor held on). (The manual does not give the colour.) Compressor symbol: red flashing fast |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | LED fan onEvaporator fan output is on. (The manual does not give the colour.) Fan symbol: red steady |
| Full Gauge MT-512E Log[121] | LED cooling onCooling output is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Full Gauge MT-512E Log[121] | LED heating onHeating output is on. (The manual does not give the colour.) Heating symbol: red steady |
| Temperzone UC7 unit controller[101] | Comp light onCompressor contactor output (CMC) is energised. (The manual does not give the colour.) Compressor symbol: green steady |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | Relay LEDs onThe associated relay output is energised. (The manual does not give the colour.) Symbol: green steady |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red blink (fast, ~250 ms) / yellow dark / green darkDrive running: red flashes once about every 250 ms. Compressor symbol: red flashing fast |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | Icon compressor onCompressor is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | Icon evaporator fan onEvaporator fan is running. (The manual does not give the colour.) Fan symbol: red steady |
| Dixell XR/XW (True cabinets)[145] | Icon compressor (snowflake) onCompressor is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XR/XW (True cabinets)[145] | Icon fan onEvaporator or condenser fan is running. (The manual does not give the colour.) Fan symbol: red steady |
| Taylor 736 soft serve freezer[153] | Ice cream cone icon flashingProduct in the barrel is not yet at dispensing consistency (freezing). (The manual does not give the colour.) Compressor symbol: white ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Taylor 736 soft serve freezer[153] | Beater icon onBeater motor is on. (The manual does not give the colour.) Symbol: white steady |
| Taylor 736 soft serve freezer[153] | Agitator icon onHopper agitator is on. (The manual does not give the colour.) Symbol: white steady |
| Taylor 736 soft serve freezer[153] | AUTO button litAuto mode: refrigeration system is active. (The manual does not give the colour.) Compressor symbol: white steady |
| Taylor 736 soft serve freezer[153] | MIX HOPPER button litHopper agitator is on. (The manual does not give the colour.) Symbol: white steady |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | Icon continuous cycle onContinuous cycle is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | Icon compressor onCompressor is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | Icon evaporator fan onEvaporator fan is running. (The manual does not give the colour.) Fan symbol: red steady |
| alpha innotec WWB 190 DHW heat pump[169] | Symbol electric heater onElectric backup heater is on. (The manual does not give the colour.) Heating symbol: white steady |
| alpha innotec WWB 190 DHW heat pump[169] | Symbol heat pump operationHeat pump (compressor) is running. (The manual does not give the colour.) Compressor symbol: white steady |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | LED coolingCooling is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | LED fanThe evaporator fans are running. (The manual does not give the colour.) Fan symbol: red steady |
| Danfoss AK-PC 782A/782B[38] | LED DO1-DO8 onThe corresponding relay output is on. (The manual does not give the colour.) Symbol: green steady |
| Danfoss AK-PC 782A/782B[38] | AK-XM 208C LED step OPEN greenThe stepper valve output is opening. Symbol: green steady |
| Danfoss AK-PC 782A/782B[38] | AK-XM 208C LED step CLOSE greenThe stepper valve output is closing. Symbol: green steady |
| Heatcraft Beacon II[30] | Display CooCooling: valve open and compressor running (slave evaporators show only this). Compressor symbol: red steady |
| Heatcraft Beacon II[30] | Display PdnPumpdown at the end of a cooling cycle: valve closed, compressor pumping the suction side down. Compressor symbol: red steady |
| Danfoss ETC (True cabinets)[142] | Icon compressorThe compressor is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Danfoss ETC (True cabinets)[142] | Icon evaporator fanThe evaporator fan is running. (The manual does not give the colour.) Fan symbol: red steady |
| Danfoss EKC 202A/B/C[2] | LED refrigeration steadyCooling relay is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Danfoss EKC 202A/B/C[2] | LED fan steadyFan relay is on. (The manual does not give the colour.) Fan symbol: red steady |
| Copeland EXD-SH1/2[26] | LED circuit 1 ONCircuit 1 is switched on (enable input closed) and controlled. (The manual does not give the colour.) Symbol: red steady |
| Copeland EXD-SH1/2[26] | LED circuit 2 ONCircuit 2 is switched on (EXD-SH2 only). (The manual does not give the colour.) Symbol: red steady |
| Copeland EXD-SH1/2[26] | LED valve steadyThe valve of the shown circuit is in regulation. (The manual does not give the colour.) Symbol: red steady |
| Copeland EXD-SH1/2[26] | LED valve opening blinkingThe valve is opening. (The manual does not give the colour.) Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland EXD-SH1/2[26] | LED valve closing blinkingThe valve is closing. (The manual does not give the colour.) Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss VLT HVAC Basic Drive FC 101[70] | LED above Auto OnThe drive is in auto mode, controlled via terminals or serial bus. (The manual does not give the colour.) Symbol: green steady |
| Carel Heos[18] | Icon compressorMain screen: the compressor output is on. (The manual does not give the colour.) Compressor symbol: white steady |
| Carel Heos[18] | Icon evaporator fanMain screen: the evaporator fan output is on. (The manual does not give the colour.) Fan symbol: white steady |
| Carel Heos[18] | Power+ LED RUN/FAULT greenThe Power+ drive is running the compressor. Compressor symbol: green steady |
| HTPG EcoNet enabled unit coolers[162] | Relay LED on (controller board)The relay next to the LED is energised (e.g. Aux 1 fans full speed, Aux 1 + Aux 2 fans half speed, defrost relays during defrost). (The manual does not give the colour.) Symbol: red steady |
| LAE AT1-5/AT2-5[166] | Indicator thermostat outputThe thermostat (compressor or heating) output is on. (The manual does not give the colour.) Compressor symbol: red steady |
| LAE AR2/BR1/BIT25 and BR+/CD25/TM (True cabinets)[146] | Icon compressorThe compressor is running. (The manual does not give the colour.) Compressor symbol: red steady |
| LAE AR2/BR1/BIT25 and BR+/CD25/TM (True cabinets)[146] | Icon evaporator fanThe evaporator fan is running. (The manual does not give the colour.) Fan symbol: red steady |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | Group icon greenMJ-310E: the group is running (on). green steady |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | Group icon blueMJ-310E block/building view: only the fan unit is running. Fan symbol: blue steady |
| Full Gauge MT-514E Faston[122] | LED coolingThe cooling output is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Full Gauge MT-514E Faston[122] | LED heatingThe heating output is on. (The manual does not give the colour.) Heating symbol: red steady |
| Full Gauge MT-514E Faston[122] | Display rEFrProcess stage: cooling. (The manual does not give the colour.) Compressor symbol: red steady |
| Full Gauge MT-514E Faston[122] | Display Hot,Process stage: heating. (The manual does not give the colour.) Heating symbol: red steady |
| NIBE F1255 ground source heat pump[78] | Board LED PWM1/PWM2 orangeThe PWM output is active (PWM1 heating medium pump GP1, PWM2 brine pump GP2 on the base card). Pump symbol: orange steady |
| NIBE F1255 ground source heat pump[78] | Board LED K1-K4 orangeThe relay is engaged (base card: K1 reversing valve, K2 brine pump, K3 heating medium pump, K4 compressor heater). Symbol: orange steady |
| NIBE F1255 ground source heat pump[78] | Heater card LED K1-K10 orangeImmersion heater card: the relay for that heater step or supply phase is engaged. Heating symbol: orange steady |
| NIBE F1255 ground source heat pump[78] | Inverter status LED orange steadyThe compressor is running normally. Compressor symbol: orange steady |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | LED cold onThe compressor (cooling) output is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | LED fans onThe evaporator fans are on. (The manual does not give the colour.) Fan symbol: red steady |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | LED hot mode onHeating mode: the heater is being called. (The manual does not give the colour.) Heating symbol: red steady |
| RDM Mercury AC and roof top unit controllers[130] | LED compressor onThe compressor relay is on. (The manual does not give the colour.) Compressor symbol: red steady |
| RDM Mercury AC and roof top unit controllers[130] | LED evaporator pumpThe evaporator pump relay is on. (The manual does not give the colour.) Pump symbol: red steady |
| RDM Mercury AC and roof top unit controllers[130] | LED condenser pumpThe condenser pump relay is on. (The manual does not give the colour.) Pump symbol: red steady |
| RDM ML Controller case controller[134] | LED coolingCooling (refrigeration output) is on. (The manual does not give the colour.) Compressor symbol: red steady |
| RDM ML Controller case controller[134] | LED fansThe fans are on. (The manual does not give the colour.) Fan symbol: red steady |
| Taylor C392/C393/C394 frozen beverage freezers[150] | Icon refrigeration valveThe barrel refrigeration (liquid line) valve is open. (The manual does not give the colour.) Compressor symbol: white steady |
| Taylor C392/C393/C394 frozen beverage freezers[150] | PNR LED red slow flashingProduct Not Ready: the barrel is freezing down or has warmed above 0 °C in Auto, or is in Defrost/Rest/Hold; stops when the product is ready. Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Full Gauge TC-900E Log[118] | LED compressor onThe compressor (cooling) output is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Full Gauge TC-900E Log[118] | LED fanThe fan output is on. (The manual does not give the colour.) Fan symbol: red steady |
| Full Gauge TC-900E Log[118] | Display rEFrProcess stage: cooling. (The manual does not give the colour.) Compressor symbol: red steady |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | Symbol compressor power partly filledThe compressor runs at part load. (The manual does not give the colour.) Compressor symbol: white steady |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | Symbol compressor power fullThe compressor runs at full load. (The manual does not give the colour.) Compressor symbol: white steady |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | Symbol electric back-up heater flashingThe electric back-up heater is running (for heating or hot water, shown with that mode symbol). (The manual does not give the colour.) Heating symbol: white ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | Symbol heating modeHeating mode active. (The manual does not give the colour.) Heating symbol: white steady |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | Symbol hot waterDomestic hot water generation active. (The manual does not give the colour.) Water symbol: white steady |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | Symbol cooling modeCooling mode active. (The manual does not give the colour.) Compressor symbol: white steady |
| Dixell XM669K/XM679K[50] | Icon cooling onCooling output (valve injection) is active. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XM669K/XM679K[50] | Icon fan onThe fan output is active. (The manual does not give the colour.) Fan symbol: red steady |
| Dixell XR70CX[54] | LED compressor onThe compressor is enabled. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XR70CX[54] | LED fan onThe fans are enabled. (The manual does not give the colour.) Fan symbol: red steady |
| Danfoss AK-CC 550A[3] | Icon compressor steadyRefrigeration/compressor relay is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Danfoss AK-CC 550A[3] | Icon fan steadyFan relay is on. (The manual does not give the colour.) Fan symbol: red steady |
| Carel ir33[11] | Icon compressor steadyCompressor is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Carel ir33[11] | Icon fan steadyEvaporator fan is running. (The manual does not give the colour.) Fan symbol: red steady |
| Carel ir33[11] | Icon continuous cycle steadyContinuous cycle (forced cooling) is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Carel ir33 universale[19] | Icon output 1-4 steadyThe numbered output is active. (The manual does not give the colour.) Symbol: red steady |
| Danfoss AK-CC55 Water Loop[35] | Display icon cooling steadyCooling is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Danfoss AK-CC55 Water Loop[35] | Display icon fan steadyFan is running. (The manual does not give the colour.) Fan symbol: red steady |
| Danfoss Optyma control AK-RC 113[39] | Icon cold call steadyCooling is being called for. (The manual does not give the colour.) Compressor symbol: red steady |
| Danfoss Optyma control AK-RC 113[39] | Icon fan steadyFans are called for. (The manual does not give the colour.) Fan symbol: red steady |
| Danfoss Optyma control AK-RC 113[39] | Icon hot mode steadyHeaters are switched on (hot mode). (The manual does not give the colour.) Heating symbol: red steady |
| Danfoss AK-RC 251[47] | Icon fan steadyEvaporator fans are running. (The manual does not give the colour.) Fan symbol: red steady |
| Danfoss AK-RC 251[47] | Icon solenoid steadyCooling solenoid valve is energised. (The manual does not give the colour.) Symbol: red steady |
| Danfoss AK-RC 251[47] | Icon compressor steadyCompressor is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Danfoss AK-RC 251[47] | Icon continuous cycle steadyContinuous cycle mode is active. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XR06CX[51] | LED compressor steadyCompressor is enabled. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XR06CX[51] | LED fan steadyFan output is enabled. (The manual does not give the colour.) Fan symbol: red steady |
| Dixell XW60K/XW60L[55] | LED compressor steadyCompressor is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XW60K/XW60L[55] | LED fan steadyFan is running. (The manual does not give the colour.) Fan symbol: red steady |
| Dixell XW60K/XW60L[55] | LED fast freezing steadyFast freezing cycle is running (XW60K). (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XW60K/XW60L[55] | LED continuous cycle steadyContinuous cycle is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Carel µC2SE for process chiller[59] | Icon 1/2 amber steadyCompressor 1 and/or 2 is running. Compressor symbol: orange steady |
| Carel µC2SE for process chiller[59] | Icon compressor amber steadyAt least one compressor is running. Compressor symbol: orange steady |
| Carel µC2SE for process chiller[59] | Icon pump amber steadyCondenser pump/fan is on. Pump symbol: orange steady |
| Carel µC2SE for process chiller[59] | Icon fan amber steadyCondenser fan is running. Fan symbol: orange steady |
| Carel µC2SE for process chiller[59] | Icon heater amber steadyHeater is on. Heating symbol: orange steady |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | Symbol compressorCompressor/cooling function is active. (The manual does not give the colour.) Compressor symbol: red steady |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | Symbol fanEvaporator fan is running. (The manual does not give the colour.) Fan symbol: red steady |
| Full Gauge TC-940R[119] | LED REFR steadyCompressor or liquid solenoid output is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Full Gauge TC-940R[119] | LED FANS steadyEvaporator fan output is on. (The manual does not give the colour.) Fan symbol: red steady |
| Castel 5650E/5658E electronic oil level regulator (R744)[123] | LED OIL FILLING yellow flashingOil injection with the solenoid valve open. Symbol: yellow ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Castel 5650E/5658E electronic oil level regulator (R744)[123] | LED OIL FILLING yellow steadyInjection cycle running, solenoid valve closed between pulses. Symbol: yellow steady |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | Remote operation lamp steadyUnit is running. (The manual does not give the colour.) Power lamp: green steady |
| True Ice TI/TCIM ice machines[147] | Real-time screen component greenThe component is energised. Symbol: green steady |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | Auto key litFreezer is in Auto mode. (The manual does not give the colour.) Compressor symbol: green steady |
| Dixell XR03CX/XR04CX (Hillphoenix display cases)[159] | LED compressor steadyCompressor is enabled. (The manual does not give the colour.) Compressor symbol: red steady |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Digital I/O card LED red onRelay output 1 or 2 is on. Auxiliary output symbol: red steady |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Output board LED onOutput is ON (closed or open path depends on the fail-safe DIP switch). (The manual does not give the colour.) Auxiliary output symbol: red steady |
| Danfoss Optyma Plus[4] | LED refrigeration steadyLit while the compressor/refrigeration relay is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Danfoss Optyma Plus[4] | LED fan steadyLit while the condenser fan runs (speed-control output or fan relay). (The manual does not give the colour.) Fan symbol: red steady |
| Carel μC2SE[8] | LED compressor 1/2 steadyCompressor 1 and/or 2 is running. Compressor symbol: orange steady |
| Carel μC2SE[8] | LED compressor (any) steadyAt least one compressor is on. Compressor symbol: orange steady |
| Carel μC2SE[8] | LED pump/fan steadyPump/fan output is on. Pump symbol: orange steady |
| Carel μC2SE[8] | LED condenser fan steadyCondenser fan is active. Fan symbol: orange steady |
| Dixell XR60CX[12] | LED compressor (❄) steadyCompressor output is enabled. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XR60CX[12] | LED fan steadyEvaporator fans are enabled. (The manual does not give the colour.) Fan symbol: red steady |
| Carel EVD evolution / EVD evolution twin[16] | LED OPEN steadyDriver is opening the expansion valve. (The manual does not give the colour.) Symbol: green steady |
| Carel EVD evolution / EVD evolution twin[16] | LED CLOSE steadyDriver is closing the expansion valve. (The manual does not give the colour.) Symbol: green steady |
| Carel SmartCella / SmartCella 3PH[24] | Compressor icon steadyCompressor is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Carel SmartCella / SmartCella 3PH[24] | Fan icon steadyEvaporator fan is on. (The manual does not give the colour.) Fan symbol: red steady |
| Carel SmartCella / SmartCella 3PH[24] | LED COMPRESSOR yellow steady (3PH panel)Power is available at the compressor terminals. Compressor symbol: yellow steady |
| Carel SmartCella / SmartCella 3PH[24] | LED EVAPORATOR FAN yellow steady (3PH panel)Power is available at the evaporator fan terminals. Fan symbol: yellow steady |
| Danfoss AK-CC 450[32] | LED refrigeration steadyRefrigeration (compressor/valve relay) is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Danfoss AK-CC 450[32] | LED fan steadyFan relay is on. (The manual does not give the colour.) Fan symbol: red steady |
| Danfoss AK-CC 750[36] | LED DO1–DO8 steadyThe corresponding relay output is on. (The manual does not give the colour.) Symbol: green steady |
| Danfoss AK-CC 750[36] | Display LED 2 (refrigeration) steadyRefrigeration relay on (EKA display front LED). (The manual does not give the colour.) Compressor symbol: red steady |
| Danfoss AK-CC 750[36] | Display LED 4 (fan) steadyFan relay on (EKA display front LED). (The manual does not give the colour.) Fan symbol: red steady |
| Danfoss EKE 100[44] | Valve LED red fast flashingValve is closing. Symbol: red flashing fast |
| Danfoss EKE 100[44] | Valve LED green fast flashingValve is opening. Symbol: green flashing fast |
| Dixell XC645D[48] | LED DGS compressor (1) steadyDigital scroll compressor (load 1) is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XC645D[48] | LED load 2–4 steadyCompressor/fan step 2, 3 or 4 is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XC645D[48] | LED DGS valve steadyThe digital scroll unloading valve is energised. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XR35CX[52] | LED compressor (❄) steadyCompressor output is enabled. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XWi70K[56] | LED compressor steadyCompressor is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XWi70K[56] | LED fan steadyFan is running. (The manual does not give the colour.) Fan symbol: red steady |
| Carel µChiller[60] | System pump icon steadySystem (user-side) pump is running. (The manual does not give the colour.) Pump symbol: red steady |
| Carel µChiller[60] | Source pump/fan icon steadySource-side device (pump or fan) is running. (The manual does not give the colour.) Fan symbol: red steady |
| Carel µChiller[60] | Compressor icon steadyCompressor is running. (The manual does not give the colour.) Compressor symbol: red steady |
| RDM Mercury 3 Twin Coil[92] | LED LLV steadyLiquid-line valve/compressor relay (relay 1 or 2) is on, section is cooling. (The manual does not give the colour.) Compressor symbol: red steady |
| RDM Mercury 3 Twin Coil[92] | LED fans steadyFan relay (relay 3) is on. (The manual does not give the colour.) Fan symbol: red steady |
| Temperzone UC8 unit controller[100] | Comp light onCompressor contactor output (CMC) is switched on. (The manual does not give the colour.) Compressor symbol: red steady |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | ON/OFF lamp green steady (wired remote)Indoor unit is in operation. Power lamp: green steady |
| Copeland Electronic Unit Controller[116] | LED compressor green steadyCompressor output is on. If lit but the compressor does not run, check the power harness and contactor wiring. Compressor symbol: green steady |
| Copeland Electronic Unit Controller[116] | LED fan 1 steadyCondenser fan 1 is on. (The manual does not give the colour.) Fan symbol: red steady |
| Copeland Electronic Unit Controller[116] | LED fan 2 steadyCondenser fan 2 is on. (The manual does not give the colour.) Fan symbol: red steady |
| Full Gauge MT-512E 2HP[120] | LED cooling steadyCooling (compressor) output is on. (The manual does not give the colour.) Compressor symbol: red steady |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | LED valve steadyValve/LLV relay (relay 1) is on; the case is cooling. Off during MOP alarm (LLV closed). (The manual does not give the colour.) Compressor symbol: red steady |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | LED fans steadyFan relay (relay 2) is on. (The manual does not give the colour.) Fan symbol: red steady |
| RDM Intuitive Superpack / Transcritical Superpack[132] | Relay LEDs steadyThe associated relay is energised. (The manual does not give the colour.) Symbol: red steady |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD runningDrive running: red LED (LED1) gives short flashes of about 250 ms. Compressor symbol: red flashing fast |
| Carel PQ (True cabinets)[144] | Compressor icon steadyCompressor is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Carel PQ (True cabinets)[144] | Fan icon steadyEvaporator fan is running. (The manual does not give the colour.) Fan symbol: red steady |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | Compressor LED steadyCompressor is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | Fan LED steadyEvaporator fan is running. (The manual does not give the colour.) Fan symbol: red steady |
| Taylor R160 frozen food dispenser[156] | Compressor enabled LED steadyCompressor output is enabled. Off while the compressor still runs suggests a stuck relay or controller fault. (The manual does not give the colour.) Compressor symbol: red steady |
| Carel MPXzero (Hillphoenix display cases)[160] | Solenoid/compressor icon steadySolenoid valve/compressor output is active. (The manual does not give the colour.) Compressor symbol: red steady |
| Carel MPXzero (Hillphoenix display cases)[160] | Evaporator fan icon steadyEvaporator fan is running. (The manual does not give the colour.) Fan symbol: red steady |
| alpha innotec BWP 190S/260S DHW heat pump[168] | Symbol heat pump (compressor) shownHeat pump compressor is running. (The manual does not give the colour.) Compressor symbol: white steady |
| alpha innotec BWP 190S/260S DHW heat pump[168] | Symbol fan shownFan (ventilation) is running. (The manual does not give the colour.) Fan symbol: white steady |
| Staff BTM5/BTM10/BTMD10/BFM10 batch freezers (with BTMD10 ice cream conservator)[194] | Compressor light steadyThe conservator compressor is running. (The manual does not give the colour.) Compressor symbol: red steady |
| NTF GM granular ice makers (GM360, GM600, GM1200, GM2000)[192] | Rotation sensor LED orange steadyNormal ice production: the start delay is over and the rotation sensor has energised the compressor contactor while it watches the auger speed. Compressor symbol: orange steady |
| NTF linear (auger) granular ice makers, G series (G160, G280, G510/G500, G1000; GB and TB versions)[196] | Rotation sensor LED orange steadyNormal operation: the compressor runs and the sensor sees the auger turning at the right speed. Compressor symbol: orange steady |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | CLOutdoor unit running in cooling. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | HtOutdoor unit running in heating. |
| Fujitsu AIRSTAGE J-II VRF – indoor units (Operation/Timer/Filter lamps)[199] | Operation steadyIndoor unit is operating. (The manual does not give the colour.) Power lamp: green steady |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | 7-segment dot flashing (1 s)The inverter compressor is running. Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| LAE BR1-27/BR1-28/BR5-A/BR5-B/BD1-28/CD25[165] | Icon thermostat output steadyThe thermostat (compressor/solenoid) output is energised. (The manual does not give the colour.) Compressor symbol: red steady |
| LAE BR1-27/BR1-28/BR5-A/BR5-B/BD1-28/CD25[165] | Icon fan output steadyThe evaporator fan output is energised. (The manual does not give the colour.) Fan symbol: red steady |
| Thermia Atella / Robust[114] | Symbol HP (compressor)The compressor is running; an F beside it means a flow switch is fitted. (The manual does not give the colour.) Compressor symbol: yellow steady |
| Thermia Atella / Robust[114] | Symbol lightning (auxiliary heater)The electric auxiliary heater is running. (The manual does not give the colour.) Heating symbol: yellow steady |
| Thermia Atella / Robust[114] | Symbol house (heating)The 3-way valve is set for space heating. (The manual does not give the colour.) Symbol: yellow steady |
| Thermia Atella / Robust[114] | Symbol tap (hot water)The 3-way valve is set for hot water production. (The manual does not give the colour.) Water symbol: yellow steady |
| Thermia Atella / Robust[114] | Symbol fanThe fan is running. (The manual does not give the colour.) Fan symbol: yellow steady |
| Carel MasterCella[7] | Compressor icon steadyCompressor is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Carel MasterCella[7] | Fan icon steadyEvaporator fan is running. (The manual does not give the colour.) Fan symbol: red steady |
| Carel MasterCella[7] | Continuous cycle icon steadyContinuous cycle is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Danfoss AK-PC 781A[37] | Extension module LED DO1–DO8 onThe output on the extension module is energised. (The manual does not give the colour.) Symbol: green steady |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | Symbol electric back-up heater with heating or hot-water symbolBack-up heater is enabled for the mode whose symbol is shown beside it. (The manual does not give the colour.) Heating symbol: white steady |
| Carel ir33+ VCC[20] | Compressor icon steadyThe compressor is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Carel ir33+ VCC[20] | Fan icon steadyThe evaporator fans are running. (The manual does not give the colour.) Fan symbol: red steady |
| Carel ir33+ VCC[20] | Continuous cycle icon steadyThe continuous cycle function is running. (The manual does not give the colour.) Compressor symbol: red steady |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | LED fans steady (Control Thermostat)The relay set for the fans is on. (The manual does not give the colour.) Fan symbol: red steady |
| Pego 202BASE electronic board[167] | LED cold (compressor) steadyThe compressor is called. (The manual does not give the colour.) Compressor symbol: red steady |
| Pego 202BASE electronic board[167] | LED fans steadyThe evaporator fans are on. (The manual does not give the colour.) Fan symbol: red steady |
| Pego 202BASE electronic board[167] | LED hot mode steadyThe heater is called (hot mode). (The manual does not give the colour.) Heating symbol: red steady |
| Dixell XW270L/XW271L[9] | LED compressor onThe compressor output is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XW270L/XW271L[9] | LED fan onThe evaporator fan is running. (The manual does not give the colour.) Fan symbol: red steady |
| Dixell XW270L/XW271L[9] | LED fast freezing onThe fast freezing (continuous) cycle is active. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XW270L/XW271L[9] | LED heater on (XW271L)XW271L only: the anti-condensing heater relay is energised. (The manual does not give the colour.) Heating symbol: red steady |
| Eliwell ID 974[13] | LED compressor onThe compressor (relay 1) is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Eliwell ID 974[13] | LED fan onThe evaporator fan is running. (The manual does not give the colour.) Fan symbol: red steady |
| Evco EV3203[107] | LED compressor steadyThe compressor is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Evco EV3203[107] | LED evaporator fan steadyThe evaporator fan is running. (The manual does not give the colour.) Fan symbol: red steady |
| Evco EV3 300 series[108] | LED OUT1 steadyThe regulation output is on. (The manual does not give the colour.) Compressor symbol: red steady |
| Evco EVK214[109] | LED compressor steadyThe compressor is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Evco EVK214[109] | LED evaporator fan steadyThe evaporator fan is running. (The manual does not give the colour.) Fan symbol: red steady |
| Evco EVK214[109] | LED multifunction steady (u1 = 3, compressor 2)Compressor 2 is running. (The manual does not give the colour.) Compressor symbol: red steady |
The lamp shows that the compressor or the unit is running, or that there is a demand for cooling or heating.
Check: Nothing to do; compare with what the unit should be doing right now.
Status: start delay or anti-short-cycle timer
| Controller | Code |
|---|---|
| Copeland Digital Compressor Controller[61] | POWER LED green flashingThe two-minute anti-short-cycle timer is running after a compressor stop (only on some module versions). Power lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland PerformanceAlert diagnostic module[62] | LED green flashingThe module is keeping the compressor off for the set minimum off time. green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland EazyCool ZX (XCM25D)[5] | LED compressor flashingAnti-short-cycle delay is running before the compressor may start. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel MPXone[21] | Icon solenoid/compressor flashingCompressor protection timers are running, or duty-setting OFF time. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel µRack[25] | Icons 1–4 (steps) flashingA step is called on or off but is waiting for its delay times to expire. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland Large ZX 22–30 HP[29] | LED 1 flashingCompressor 1 is ready to start (waiting for delay). (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland Large ZX 22–30 HP[29] | LED 2 flashingCompressor 2 is ready to start (waiting for delay). (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XR460C[53] | Icon compressor 1 flashingAnti-short-cycle delay running for compressor 1. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XR460C[53] | Icon compressor 2 flashingAnti-short-cycle delay running for compressor 2. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Pego ECP200 EXPERT PULSE[89] | Icon cold call (compressor) flashingCooling is called but the compressor waits for protection time C1. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Kriwan INT69 Y Diagnose[97] | LED red 3 / orange 5Reset delay running after a general (supply) error; the motor stays off until it expires. Alarm symbol: red ●●● → orange ●●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | Icon continuous cycle flashingContinuous cycle is requested and waiting. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | Icon compressor flashingCompressor is requested but waiting (protection times). (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| BAC TrilliumSeries adiabatic cooler TRF[174] | Message Pump X Anti-Recycle Timer ActiveThe adiabatic pre-cooler pump is held off by its anti-short-cycle timer. (The manual does not give the colour.) Pump symbol: white steady |
| Heatcraft Beacon II[30] | Display dLYStart delay: the valve is opening before the compressor starts, or the 4-minute hold-off is running. Symbol: red steady |
| LAE AT1-5/AT2-5[166] | Display RECRecovery after defrost: the room is pulling down before normal display returns. (The manual does not give the colour.) Defrost symbol: red steady |
| Full Gauge MT-514E Faston[122] | Display dEL,Process stage: start-up delay after power-on. (The manual does not give the colour.) red steady |
| Danfoss Optyma iCO2[46] | Display Sr1Restart delay after a high-pressure stop. Symbol: green steady |
| Danfoss Optyma iCO2[46] | Display Sr2Restart delay after a fan motor fault. Fan symbol: green steady |
| Danfoss Optyma iCO2[46] | Display Sr3Restart delay after high discharge temperature. Symbol: green steady |
| Danfoss Optyma iCO2[46] | Display Sr4Restart delay after high receiver pressure. Symbol: green steady |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | LED cold flashingCooling is called but waiting for the compressor protection delay (C1). (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM Mercury AC and roof top unit controllers[130] | LED compressor flashingCompressor start delay: condenser pump pre-run, or holding off because the starts-per-hour limit is reached. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM ML Controller case controller[134] | Display recControl state: recovery (pulling down after defrost or an off period). (The manual does not give the colour.) Symbol: red steady |
| Taylor R280 fry dispenser[158] | Display rF OFF flashingThe compressor cannot restart until the 2-minute short-cycle delay has passed. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Full Gauge TC-900E Log[118] | Display dEL,Process stage: start-up delay after power-on. (The manual does not give the colour.) red steady |
| Full Gauge TC-900E Log[118] | Display Fan,Process stage: fan delay after defrost. (The manual does not give the colour.) Fan symbol: red steady |
| Bitzer VARIPACK FMY+/FMU+ .. FSW+ (frequency inverter)[58] | Symbol start-to-start intervalThe minimum time between compressor starts has not yet expired. (The manual does not give the colour.) Compressor symbol: white steady |
| Dixell XM669K/XM679K[50] | Icon cooling blinkingA delay is running before the cooling output changes. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XM669K/XM679K[50] | Icon fan blinkingA fan delay is running. (The manual does not give the colour.) Fan symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XM669K/XM679K[50] | Icon defrost blinkingA defrost-related delay is running. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XM669K/XM679K[50] | Icon AUX blinkingA delay is running for the auxiliary relay. (The manual does not give the colour.) Auxiliary output symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XR70CX[54] | LED compressor flashingAnti-short-cycle delay is running. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XR70CX[54] | LED fan flashingFan delay after defrost is running. (The manual does not give the colour.) Fan symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33[11] | Icon compressor flashingCompressor start is being held back by protection timers. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33[11] | Icon fan flashingFan start is blocked by an external disable or a running procedure (e.g. post-drip delay). (The manual does not give the colour.) Fan symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33[11] | Icon defrost flashingDefrost is requested but held back by an external disable or a running procedure. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33[11] | Icon continuous cycle flashingContinuous cycle is requested but blocked, e.g. by the minimum compressor off time. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33 universale[19] | Icon output 1-4 flashingThe numbered output is requested but delayed by protection times, an external disable or another procedure. (The manual does not give the colour.) Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-RC 251[47] | Icon solenoid flashingSolenoid should open but a delay or protection prevents it. (The manual does not give the colour.) Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-RC 251[47] | Icon compressor flashingCompressor should run but a delay or protection prevents it. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XR06CX[51] | LED compressor flashingAnti-short-cycle delay is running (parameter AC). (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XW60K/XW60L[55] | LED compressor flashingAnti-short-cycle delay is running (also flashes with the fan LED while programming). (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel µC2SE for process chiller[59] | Icon 1/2 amber flashingCompressor start has been requested and is waiting. Compressor symbol: orange ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel µC2SE for process chiller[59] | Icon pump amber flashingPump/fan start has been requested and is waiting. Pump symbol: orange ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel µC2SE for process chiller[59] | Icon chiller mode amber flashingChiller mode has been requested and is waiting. Symbol: orange ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Kriwan INT69 PYF Diagnose[95] | LED red 2 / orange 4Phase monitoring: switch-back delay is running. Symbol: red ●● → orange ●●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Castel 5650E/5658E electronic oil level regulator (R744)[123] | LED OIL GOOD green flashingOil level is low but injection has not started yet. Symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Temperzone UC6 unit controller[135] | DS1 digit 1Anti-rapid-cycle timer is blocking a compressor start. (The manual does not give the colour.) Compressor symbol: red steady |
| Temperzone UC6 unit controller[135] | DS1 digit 2Minimum run timer is keeping the compressor on. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XR03CX/XR04CX (Hillphoenix display cases)[159] | LED compressor flashingAnti-short-cycle delay is running (parameter AC). (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel μC2SE[8] | LED compressor 1/2 flashingCompressor start is requested but waiting (timings/protection). Compressor symbol: orange ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel μC2SE[8] | LED pump/fan flashingPump/fan start is requested but not yet running. Pump symbol: orange ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XR60CX[12] | LED compressor (❄) flashingAnti-short-cycle delay is running; compressor waits. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XR60CX[12] | LED fan flashingFan delay after defrost is running. (The manual does not give the colour.) Fan symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel SmartCella / SmartCella 3PH[24] | Compressor icon flashingCompressor start is waiting, delayed or blocked by protection times. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel SmartCella / SmartCella 3PH[24] | Fan icon flashingFan start is waiting for protection times or another procedure. (The manual does not give the colour.) Fan symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel SmartCella / SmartCella 3PH[24] | Defrost icon flashingDefrost is requested but delayed by protection times or another procedure. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel SmartCella / SmartCella 3PH[24] | Continuous cycle icon flashingContinuous cycle is requested but delayed by protection times. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XC645D[48] | LED load 1–4 flashing 1 HzThe load is waiting to start (safety timers). (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Dixell XR35CX[52] | LED compressor (❄) flashingAnti-short-cycle delay is running. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XWi70K[56] | LED compressor flashingAnti-short-cycle delay is running (also flashes, together with the fan LED, in programming mode). (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland Electronic Unit Controller[116] | LED compressor green flashingAnti-short-cycle delay is running. Compressor symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland Electronic Unit Controller[116] | LED compressor green off with demandCompressor is off: pressure above cut-in setting or jumper cable not connected. Compressor symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | Compressor LED flashingCompressor start delayed, in protection time or blocked. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Taylor R160 frozen food dispenser[156] | Compressor enabled LED flashingAnti-short-cycle delay is running. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel MPXzero (Hillphoenix display cases)[160] | Solenoid/compressor icon flashingProtection timings are running before the output can switch. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel MPXzero (Hillphoenix display cases)[160] | Defrost icon flashingDefrost is waiting to start. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Krack KR-A2L unit cooler (KE2 Evap leak sensor alarms)[164] | Copeland sensor green blink 1 Hz + alarm 1 redGas gone; alarm 1 resets automatically after about 10 s. Alarm symbol: green ● → red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| NTF GM granular ice makers (GM360, GM600, GM1200, GM2000)[192] | Delay timer lamp blinkingAll safety devices are closed and the gear motor runs; the delay timer is counting down (about 8–10 minutes) before it starts the compressor. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Staff BTM5/BTM10/BTMD10/BFM10 batch freezers (with BTMD10 ice cream conservator)[194] | Compressor light flashingThe compressor wants to start but waits for the set start delay to run out. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| NTF linear (auger) granular ice makers, G series (G160, G280, G510/G500, G1000; GB and TB versions)[196] | Rotation sensor LED orange blinkingAll safety devices are closed and the gear motor turns; the 8-minute start delay is running before the compressor is allowed to start. Switching off and on restarts the delay. Compressor symbol: orange ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | Icon defrost flashingDefrost is requested and waiting to start. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel MasterCella[7] | Compressor icon flashingCompressor start is held back by its safety timers. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel MasterCella[7] | Fan icon flashingFan start is blocked by an external disable or a running procedure. (The manual does not give the colour.) Fan symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel MasterCella[7] | Defrost icon flashingDefrost is requested but blocked by an external disable or a running procedure. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel MasterCella[7] | Continuous cycle icon flashingContinuous cycle is requested but blocked, e.g. by the minimum compressor off time. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33+ VCC[20] | Compressor icon flashingCompressor start is requested but held back by protection times. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33+ VCC[20] | Fan icon flashingFan start is requested but delayed by protection times or another procedure. (The manual does not give the colour.) Fan symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33+ VCC[20] | Defrost icon flashingDefrost is requested but delayed by protection times or another procedure. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33+ VCC[20] | Continuous cycle icon flashingContinuous cycle is requested but held back by protection times. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XW270L/XW271L[9] | LED compressor flashingAnti-short-cycle delay is counting down; also flashes in programming mode. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Eliwell ID 974[13] | LED compressor flashingCompressor start is held back by a delay, protection or blocked enabling. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Evco EV3203[107] | LED compressor blinkingCompressor protection delay is running, or the setpoint is being changed. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Evco EV3203[107] | LED evaporator fan blinkingThe evaporator fan is held off (fan stop after defrost). (The manual does not give the colour.) Fan symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Evco EV3 300 series[108] | LED OUT1 blinkingThe output's protection delay is running. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Evco EVK214[109] | LED compressor blinkingCompressor protection is running (C0, C1, C2, i7) or the setpoint is being changed. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Evco EVK214[109] | LED evaporator fan blinkingThe evaporator fan is held off (F3). (The manual does not give the colour.) Fan symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Evco EVK214[109] | LED multifunction blinking (u1 = 3, compressor 2)Compressor 2 start delay is running (C9). (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
A timer is running (anti-short-cycle or minimum off time) before the compressor may start again.
Check: Wait for the timer; if it never ends, check the controller and its settings.
Status: power on, standby or waiting
| Controller | Code |
|---|---|
| Copeland Digital Compressor Controller[61] | POWER LED green steady24 VAC supply is present at the controller's power terminals. Power lamp: green steady |
| Copeland PerformanceAlert diagnostic module[62] | LED green steadySupply voltage is present at the module's power terminals. green steady |
| Danfoss Optyma Plus Module B Plus (P02)[45] | LED1 red steadyPower LED: Module B Plus has supply voltage. red steady |
| Kriwan INT69 F Diagnose[94] | LED green steadyNo fault; the machine is stopped and ready to run. green steady |
| Kriwan INT69 PYF Diagnose[95] | LED green steadyNo fault; the machine is stopped and ready to run. green steady |
| Kriwan INT69 YF Diagnose[98] | LED green steadyNo fault; the machine is stopped and ready to run. green steady |
| Kriwan INT69 UY Diagnose[96] | LED green steadyNo fault; the machine is stopped and ready to run. green steady |
| Kriwan INT69 Y Diagnose[97] | LED green steadyNo fault; the machine is stopped and ready to run. green steady |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | LED yellow steadyKB drive ST LED: drive is in stop mode. yellow steady |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | PWR LED green steadyKB drive PWR LED: bus and logic power supply is OK. green steady |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | Controller POWER LED green steadyCondenser controller: supply power is connected. green steady |
| Danfoss Gas Sensor DGS[71] | Keypad LED green steadyKeypad status LED: operating voltage is present. green steady |
| Danfoss AK-PC 781A[37] | LED Power onController has supply voltage. (The manual does not give the colour.) Power lamp: green steady |
| Danfoss AK-PC 781A[37] | Extension module LED power onExtension module has supply voltage. (The manual does not give the colour.) Power lamp: green steady |
| Danfoss Optyma Plus Module B Plus (P02)[45] | LED1 offModule B Plus has no supply voltage. Power lamp: red ● · 1 s on, 1 s off (timing assumed, not stated in the manual) |
| Bitzer VARIPACK FDU+ .. FKU+ (frequency inverter)[57] | Signal lamp H6 (ready to operate) onCompressor/inverter is ready to operate. (The manual does not give the colour.) Power lamp: green steady |
| AHT plug-in cases with Danfoss controller (Paris, Ibiza, Malta, Manhattan)[85] | Decimal point (comma) onlyCooling has been switched off with the SC button (standby). (The manual does not give the colour.) Power lamp: red steady |
| LG Multi V 5 VRF outdoor units[77] | Outdoor PCB LED blinkingOutdoor PCB has power and is running; if not blinking check supply and PCB. (The manual does not give the colour.) Power lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Störk-Tronic ST121 / ST501 / ST551[93] | Right decimal point on (standby)Controller is in standby (when L7 = 2). Power lamp: red steady |
| Störk-Tronic ST121 / ST501 / ST551[93] | Right decimal point flashing (standby)Controller is in standby (when L7 = 3). Power lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | LED control functions shutdown onControl and alarms are switched off; the unit only shows temperature (OFF alternates on display). (The manual does not give the colour.) Power lamp: red steady |
| Full Gauge MT-512E Log[121] | LED control functions OFF onControl functions are switched off; the controller only indicates temperature. (The manual does not give the colour.) Power lamp: red steady |
| Temperzone UC7 unit controller[101] | Power light onController has 230 V supply; if off check mains, breaker, board fuse and phase rotation relay. (The manual does not give the colour.) Power lamp: green steady |
| Temperzone UC7 unit controller[101] | Display flashing dotUnit on but no compressor demand (COMP input/thermostat/BMS signal absent). (The manual does not give the colour.) Power lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red dark / yellow lit / green darkReset mode: yellow on for about 6 s after power-up. Power lamp: yellow steady |
| ActronAir Aires and Advance 19–25 kW[137] | VSD LEDs red blink / yellow dark / green darkStandby: red flashes once about every 1 s. Power lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | Blank display with decimal pointControl has been switched off with the power button (shows oFF first). (The manual does not give the colour.) Power lamp: red steady |
| Taylor 736 soft serve freezer[153] | STANDBY button litStandby mode: hopper and barrel kept below 4.4 °C. (The manual does not give the colour.) Power lamp: white steady |
| Taylor 736 soft serve freezer[153] | STOP button litMachine is off. (The manual does not give the colour.) Power lamp: white steady |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | D501 (red) onIndoor main microcomputer is running (on from power-up). Power lamp: red steady |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | D403 (red) onRemote controller power supply is on. Power lamp: red steady |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Display CPUnit switched off remotely. (The manual does not give the colour.) Power lamp: white steady |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | Power LED greenThe controller has supply voltage. Power lamp: green steady |
| Danfoss AK-PC 782A/782B[38] | LED Power onThe controller has 24 V supply. (The manual does not give the colour.) Power lamp: green steady |
| Danfoss AK-PC 782A/782B[38] | Module LED supply onThe extension module has supply voltage. (The manual does not give the colour.) Power lamp: green steady |
| Danfoss VLT HVAC Basic Drive FC 101[70] | LED On greenThe drive has supply voltage. Power lamp: green steady |
| Danfoss VLT FC 103[14] | LED On green steadyThe drive has supply voltage (mains, DC bus or external 24 V). Power lamp: green steady |
| Carel Heos[18] | Board power LED green steadyThe Heos board has supply voltage. Power lamp: green steady |
| Carel Heos[18] | Power+ LED POWER green steadyThe Power+ compressor drive is powered. Power lamp: green steady |
| LAE AT1-5/AT2-5[166] | Display OFFThe controller is in stand-by. (The manual does not give the colour.) Power lamp: red steady |
| LAE AR2/BR1/BIT25 and BR+/CD25/TM (True cabinets)[146] | Display oFFThe controller is in stand-by (refrigeration off, lights still powered). (The manual does not give the colour.) Power lamp: red steady |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | Group icon redMJ-310E: the group is stopped (off). Power lamp: red steady |
| Full Gauge MT-514E Faston[122] | Display OFF,Control functions are switched off. (The manual does not give the colour.) Power lamp: red steady |
| Full Gauge MT-514E Faston[122] | Display ----Process stage: control functions off. (The manual does not give the colour.) Power lamp: red steady |
| NIBE F1255 ground source heat pump[78] | Board LED Power green steadyBase, input or accessory card: 12 V supply is OK. Power lamp: green steady |
| NIBE F1255 ground source heat pump[78] | Comm board LED INV greenCommunication board AA123 gets supply from the inverter. Power lamp: green steady |
| NIBE F1255 ground source heat pump[78] | Comm board LED PWR greenCommunication board AA123 gets voltage from the base card. Power lamp: green steady |
| NIBE F1255 ground source heat pump[78] | Inverter power LED orangeThe inverter is powered (16 kW model only). Power lamp: orange steady |
| Danfoss Optyma iCO2[46] | Display ----The display is waiting for communication with the unit controller. Communication lamp: green steady |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | LED stand-by flashingThe controller is in stand-by and all outputs are off. (The manual does not give the colour.) Power lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel pRack pR300[22] | Terminal LED greenThe pRack controller has supply voltage. Power lamp: green steady |
| Carel pRack pR300[22] | Board LED yellowPower is connected to the pRack board. Power lamp: yellow steady |
| RDM ML Controller case controller[134] | Display OFFThe case is switched off. (The manual does not give the colour.) Power lamp: red steady |
| Taylor Icetro ISI-161TH/ISI-161TI[154] | STAND-BY lightStand-by mode: mix in barrel and hopper is only kept cold. (The manual does not give the colour.) Power lamp: red steady |
| Taylor R280 fry dispenser[158] | Power lightThe dispenser is switched on. (The manual does not give the colour.) Power lamp: red steady |
| Full Gauge TC-900E Log[118] | LED control functions shutdownControl functions are switched off; the display may go dark with only this light on. (The manual does not give the colour.) Power lamp: red steady |
| Full Gauge TC-900E Log[118] | Display OFF,Control routines are switched off. (The manual does not give the colour.) Power lamp: red steady |
| Full Gauge TC-900E Log[118] | Display ----Process stage: control functions off. (The manual does not give the colour.) Power lamp: red steady |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | OPERATION lamp green flashing 1 HzPower has been switched on or returned after a power failure; flashing stops when START/STOP is pressed. Power lamp: green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | Symbol compressor power emptyThe compressor is not running. (The manual does not give the colour.) Compressor symbol: white steady |
| Bitzer VARIPACK FMY+/FMU+ .. FSW+ (frequency inverter)[58] | Display INHIBITThe STO (safe torque off) input is de-energised, so the inverter will not start; if STO is energised and this stays, the STO input is faulty. (The manual does not give the colour.) Power lamp: white steady |
| Carel pRack pR300T (transcritical CO2)[23] | Terminal LED green steadyThe pRack is powered. Power lamp: green steady |
| Carel pRack pR300T (transcritical CO2)[23] | Board LED yellow steadyPower is connected to the pRack board. Power lamp: yellow steady |
| Sanhua SEC60x[31] | LED POWER steadyController is powered. (The manual does not give the colour.) Power lamp: red steady |
| Danfoss AK-CC55 Water Loop[35] | Controller LED green steadyController is powered. Power lamp: green steady |
| Danfoss Optyma control AK-RC 113[39] | Icon stand-by flashingPanel is in stand-by; outputs are disabled. (The manual does not give the colour.) Power lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss Optyma control AK-RC 113[39] | Display In5 alternatingStand-by set from the remote digital input. (The manual does not give the colour.) Power lamp: red steady |
| Danfoss Optyma control AK-RC 113[39] | All LEDs on at power-upNormal lamp test for a few seconds after switching on, with a short beep. (The manual does not give the colour.) Power lamp: red steady |
| Danfoss EKE 1A/1B/1C/1D[43] | Status LED green steadyController is powered. Power lamp: green steady |
| Danfoss AK-RC 251[47] | Icon stand-by steadyStand-by is on; regulation is paused. (The manual does not give the colour.) Power lamp: red steady |
| Danfoss AK-RC 251[47] | Icon stand-by flashingControlled shutdown before stand-by is in progress. (The manual does not give the colour.) Power lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XW60K/XW60L[55] | LED ON/OFF steadyUnit is in stand-by (display shows OFF); all relays are off. (The manual does not give the colour.) Power lamp: red steady |
| RDM DMTouch / miniDM[91] | LED power steadyUnit is powered. (The manual does not give the colour.) Power lamp: green steady |
| Castel 5650E/5658E electronic oil level regulator (R744)[123] | LED POWER green steadyRegulator is correctly powered. Power lamp: green steady |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | PCB LED D02 steadyPower on, microprocessor running; also lit while a DN code is being set. Power lamp: red steady |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | Remote SETTING flashing at power-onInitial settings in progress; wait until it disappears. (The manual does not give the colour.) Setup/programming symbol: white ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | Standby keys litFreezer is in Standby (e.g. after a completed heat cycle). (The manual does not give the colour.) Power lamp: green steady |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | All LEDs on at power-upLamp test while the control initialises. (The manual does not give the colour.) Power lamp: green steady |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Main board LED D1 green steadyE2 is booting. Power lamp: green steady |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Boot LED D18 green steadyE2 is booting. Power lamp: green steady |
| Copeland (CPC) E2 RX/BX/CX controller[163] | PIB LED green steadyPower is applied to the processor interface board. Power lamp: green steady |
| Pego 202BASE electronic board[167] | Display In5 alternatingStand-by set from the remote digital input. (The manual does not give the colour.) Power lamp: red steady |
| Carpigiani AES PSP[15] | All LEDs on at power-upLamp test for a few seconds after switching on. (The manual does not give the colour.) Power lamp: red steady |
| Carel EVD evolution / EVD evolution twin[16] | LED OPEN + CLOSE flashingDriver disabled: waiting for the initial configuration to be completed. (The manual does not give the colour.) Setup/programming symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel EVD evolution / EVD evolution twin[16] | LED POWER green steadyDriver is powered. Power lamp: green steady |
| Carel EVD evolution / EVD evolution twin[16] | LED POWER green offDriver has no power supply. Power lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel SmartCella / SmartCella 3PH[24] | LED POWER green steady (3PH panel)Auxiliary circuit is powered (QF2 and QS1 on). Power lamp: green steady |
| Carel SmartCella / SmartCella 3PH[24] | LED POWER green off (3PH panel)Auxiliary circuit has no power; check QF2 and main switch QS1. Power lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-CC 750[36] | LED Power steadyController module has supply voltage. (The manual does not give the colour.) Power lamp: green steady |
| Danfoss EKE 100[44] | LED power green steadyController is powered. Power lamp: green steady |
| Danfoss EKE 100[44] | LED alarm red fast flashing (first 5 s)Initial boot during the first 5 seconds after power-up. Power lamp: red flashing fast |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | LED green steadyOperating voltage is present. Power lamp: green steady |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | LED yellow slow flashingSensor is warming up after power-on. Power lamp: yellow ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Temperzone UC8 unit controller[100] | Power light onController has 230 V AC mains. (The manual does not give the colour.) Power lamp: red steady |
| Temperzone UC8 unit controller[100] | Display dash slowly flashingUnit is OFF by the remote on/off input (input open circuit). (The manual does not give the colour.) Power lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Indoor board LED1 steadyControl power is supplied to the indoor microprocessor (should always be lit). (The manual does not give the colour.) Power lamp: red steady |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Indoor board LED2 steadyPower is supplied to the remote controller (only on the unit with refrigerant address 0). (The manual does not give the colour.) Power lamp: red steady |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD reset modeDrive reset: yellow LED (LED2) on for about 6 seconds. Power lamp: yellow steady |
| ActronAir Advance / VCC / Genesis 13–17 kW[136] | Aires VSD standbyDrive in standby: red LED (LED1) flashes once for about 1 second. Power lamp: red ● · 1 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | All LEDs on at power-upLamp test for a few seconds after switching on. (The manual does not give the colour.) Power lamp: red steady |
| Taylor R160 frozen food dispenser[156] | On/Off switch litMain power to the dispenser is on. (The manual does not give the colour.) Power lamp: red steady |
| Krack KR-A2L unit cooler (KE2 Evap leak sensor alarms)[164] | Copeland sensor PWR green blink 1 Hz + red LEDs on (start-up)Initialisation after power-up; relays open until finished. Power lamp: green ● → red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | BlankDisplay blank: outdoor unit idle (stopped), no fault. |
| Fujitsu AIRSTAGE J-II VRF – indoor units (Operation/Timer/Filter lamps)[199] | Timer 3 s on / 1 s offOpposite operation mode: this unit asks for cooling while the system runs heating (or the reverse), so it waits. Set all units on the same outdoor unit to the same mode. (The manual does not give the colour.) orange ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| LAE BR1-27/BR1-28/BR5-A/BR5-B/BD1-28/CD25[165] | Icon stand-by steadyThe controller is in stand-by and does not regulate. (The manual does not give the colour.) Power lamp: red steady |
| Dixell XWi70K[56] | LED ON/OFF steadyController is in stand-by: relays off and control stopped; display shows OFF. (The manual does not give the colour.) Power lamp: red steady |
| Pego 202BASE electronic board[167] | LED stand-by flashingThe controller is in stand-by and the outputs are off. (The manual does not give the colour.) Power lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Pego 202BASE electronic board[167] | All LEDs on at power-upLamp test for a few seconds after power is switched on. (The manual does not give the colour.) Power lamp: red steady |
| Dixell XW270L/XW271L[9] | ON/OFF button LED onThe controller is switched off with the ON/OFF key; all relays and control are stopped, light and AUX keys still work. (The manual does not give the colour.) Power lamp: red steady |
| Eliwell ID 974[13] | All LEDs and display flashing at power-upLamp test for a few seconds after switching on; normal. (The manual does not give the colour.) Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| NIBE F1255 ground source heat pump[78] | MODBUS 40 LED VCC steadyMODBUS 40 supply voltage is OK. (The manual does not give the colour.) Power lamp: green steady |
| NIBE F1255 ground source heat pump[78] | SMS 40 LED BATT steadySMS 40 backup battery has voltage. (The manual does not give the colour.) Power lamp: green steady |
| NIBE F1255 ground source heat pump[78] | SMS 40 LED 4 steadySMS 40 12 V supply is OK. (The manual does not give the colour.) Power lamp: green steady |
| NIBE F1255 ground source heat pump[78] | SMS 40 LED VCC steadySMS 40 supply voltage is OK. (The manual does not give the colour.) Power lamp: green steady |
| Evco EV3 300 series[108] | LED on/stand-by steadyThe controller is switched off (stand-by). (The manual does not give the colour.) Power lamp: red steady |
| Evco EV3 300 series[108] | LED on/stand-by blinkingThe controller is being switched off. (The manual does not give the colour.) Power lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Evco EVK214[109] | LED on/stand-by steadyThe controller is in stand-by. (The manual does not give the colour.) Power lamp: red steady |
The unit has supply voltage but is waiting: standby, no demand or waiting for a signal.
Check: Check the demand signal, the setpoint and any enable or remote on/off input.
Status: information
| Controller | Code |
|---|---|
| Copeland CoreSense Protection (Discus)[63] | LED red/green flashing (RS485)The RS485 polarity LEDs on the board flash when the network wiring polarity is correct. red + green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland Stream condensing units (Next Gen CoreSense)[27] | LED orange steadyThe compressor is running in emergency mode. orange steady |
| Copeland Stream condensing units (Next Gen CoreSense)[27] | LED red steadyThe CoreSense module is in parameter-setting mode. red steady |
| Copeland ZSI scroll condensing units[28] | LED2+LED3 1 flashSwitching between automatic mode and manual EXV test mode succeeded (also shown when entering or leaving manual mode). green ● · 0.5 s on, 0.5 s off · pause 5 s (timing assumed, not stated in the manual) |
| Copeland ZSI scroll condensing units[28] | LED2 flashingManual EXV test: the valve is opening. green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland ZSI scroll condensing units[28] | LED2 steadyManual EXV test: the valve is fully open. green steady |
| Copeland ZSI scroll condensing units[28] | LED3 flashingManual EXV test: the valve is closing. green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland ZSI scroll condensing units[28] | LED3 steadyManual EXV test: the valve is at its minimum opening. green steady |
| Kriwan INT69 F Diagnose[94] | LED orange steadyNo fault and the machine is ready, but the set service interval has run out. orange steady |
| Kriwan INT69 F Diagnose[94] | LED orange flashingNo fault and the machine is running, but the set service interval has run out. orange ● · 0.35 s on, 0.35 s off |
| Kriwan INT69 F Diagnose[94] | LED red steady (Temp.)The protection relay is in parameter-setting mode. red steady |
| Kriwan INT69 F Diagnose[94] | LED red fast flashing (Temp.)The bootloader is active, e.g. while firmware is loaded or when firmware is missing. red flashing fast |
| Kriwan INT69 PYF Diagnose[95] | LED orange steadyNo fault and the machine is ready, but the set service interval has run out. orange steady |
| Kriwan INT69 PYF Diagnose[95] | LED orange flashingNo fault and the machine is running, but the set service interval has run out. orange ● · 0.35 s on, 0.35 s off |
| Kriwan INT69 YF Diagnose[98] | LED orange steadyNo fault and the machine is ready, but the set service interval has run out. orange steady |
| Kriwan INT69 YF Diagnose[98] | LED orange flashingNo fault and the machine is running, but the set service interval has run out. orange ● · 0.35 s on, 0.35 s off |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED orange 9Calibration of the rotor position sensor is in progress. orange ●●●●●●●●● · 0.25 s on, 0.25 s off · pause 3 s |
| ebm-papst EC fans with status LED (K3G310, W3G910)[74] | LED orange 16The shake-loose function is active. orange ●●●●●●●●●●●●●●●● · 0.25 s on, 0.25 s off · pause 3 s |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | Controller FAULT LED red 2 HzCondenser controller: download or start-up in progress, not yet ready for normal operation. red flashing fast (2 Hz) |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | Controller bus LED green 2 HzCondenser controller SA bus, FC bus or Modbus LED: data is being transmitted on that bus. green flashing fast (2 Hz) |
| Danfoss Gas Sensor DGS[71] | LED yellow flashingThe sensor is in special/service mode (e.g. set from the Service Tool); it times out after about 15 minutes. yellow ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss Gas Sensor DGS[71] | Keypad LED yellow slow flashingKeypad status LED: the sensor is warming up. yellow ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss Gas Sensor DGS[71] | Keypad LED yellow fast flashingKeypad status LED: special mode is active. yellow flashing fast (2 Hz) |
| Danfoss Gas Sensor DGS[71] | All LEDs on (LCD check)LCD function check from the menu: all LEDs light for about two seconds. green + yellow + red steady |
| Heatcraft A2L Refrigerant Detection System (unit coolers)[79] | LED green flashingAfter power-up the A2L controller initializes the leak sensors; this takes about 5 minutes. green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Mitsubishi Electric SUZ-KA VA4 outdoor units[103] | 9 flashesInverter check mode has started because the compressor connector is unplugged (service test). red ●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s |
| Danfoss ERC 21X[1] | Icon night mode (moon) steadyNight/energy-saving mode is active. (The manual does not give the colour.) Eco/night symbol: red steady |
| Copeland EazyCool ZX (XCM25D)[5] | LED bar onPressure is displayed in bar. (The manual does not give the colour.) Symbol: red steady |
| Copeland EazyCool ZX (XCM25D)[5] | LED bar flashingController is in programming mode. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland EazyCool ZX (XCM25D)[5] | LED PSI onPressure is displayed in psi. (The manual does not give the colour.) Symbol: red steady |
| Copeland EazyCool ZX (XCM25D)[5] | LED PSI flashingController is in programming mode. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland EazyCool ZX (XCM25D)[5] | LED service onThe service menu is being browsed. (The manual does not give the colour.) Service symbol: red steady |
| Copeland EazyCool ZX (XCM25D)[5] | LED service flashingThe fast-access menu is open. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland EazyCool ZX (XCM25D)[5] | LED alarm on (menu)The alarm menu is being browsed. (The manual does not give the colour.) Alarm symbol: red steady |
| Carel EVD ice / EVD mini[17] | Start/stop LED (decimal point) offStart/stop digital input is open; control is stopped. (The manual does not give the colour.) Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel MPXone[21] | Icon light onCabinet light is on. (The manual does not give the colour.) Light symbol: red steady |
| Carel MPXone[21] | Icon AUX onAuxiliary output is active. (The manual does not give the colour.) Auxiliary output symbol: red steady |
| Carel MPXone[21] | Icon clock onTime scheduler is active. (The manual does not give the colour.) Clock symbol: red steady |
| Carel MPXone[21] | Icon energy saving onSmooth Lines energy-saving function is active. (The manual does not give the colour.) Eco/night symbol: red steady |
| Carel MPXone[21] | Icon service onMaintenance is requested. (The manual does not give the colour.) Service symbol: red steady |
| Carel MPXone[21] | Icon HACCP onHACCP monitoring is active. (The manual does not give the colour.) HACCP symbol: red steady |
| Carel MPXone[21] | Icon + (generic function) onA configured generic function is active. (The manual does not give the colour.) Symbol: red steady |
| Carel MPXone[21] | PRG button LED onMain screen or programming mode. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Carel MPXone[21] | UP/DOWN button LED flashingA parameter value is being set. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel µRack[25] | Icon MANUFACTURER onManufacturer parameters are being configured. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Carel µRack[25] | Icon MANUFACTURER flashingAt least one device is in manual operation (times and rotation ignored). (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland Large ZX 22–30 HP[29] | LED °C onValues are shown in °C. (The manual does not give the colour.) Symbol: red steady |
| Copeland Large ZX 22–30 HP[29] | LED °C flashingController is in programming mode. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland Large ZX 22–30 HP[29] | LED service onThe service menu is being browsed. (The manual does not give the colour.) Service symbol: red steady |
| Copeland Large ZX 22–30 HP[29] | LED service flashingThe fast-access menu is being browsed. (The manual does not give the colour.) Service symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland Large ZX 22–30 HP[29] | LED ! flashing (upper)The alarm menu is being browsed. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-PC 781A[37] | LED Status quick flashAnswer from the gateway after network installation (up to 10 min). (The manual does not give the colour.) Communication lamp: green flashing fast |
| Danfoss AK-PC 781A[37] | LED Service Tool / LON / I/O extension / Display onCommunication active with Service Tool, LON network, AK-CM 102 extension or display respectively. (The manual does not give the colour.) Communication lamp: green steady |
| Danfoss AK-PC 781A[37] | LED Service Pin onThe Service Pin switch has been activated (network installation). (The manual does not give the colour.) Communication lamp: green steady |
| Dixell XEV12D[49] | LED valve offExpansion valve is closed. Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XEV12D[49] | LED communication blinkingSerial communication is present. Communication lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XEV12D[49] | LED communication offNo serial communication. Communication lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XR460C[53] | Icon °C onTemperatures shown in °C. (The manual does not give the colour.) Symbol: red steady |
| Dixell XR460C[53] | Icon °F onTemperatures shown in °F. (The manual does not give the colour.) Symbol: red steady |
| Pego ECP200 EXPERT PULSE[89] | Icon door/cold room light onCold room light is on. (The manual does not give the colour.) Light symbol: red steady |
| Pego ECP200 EXPERT PULSE[89] | Icon door/cold room light flashingDoor switch is active (door open) and cold room light is on. (The manual does not give the colour.) Door symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Pego ECP200 EXPERT PULSE[89] | Icon real-time clock onDefrosts by real-time clock are enabled. (The manual does not give the colour.) Clock symbol: red steady |
| Pego ECP200 EXPERT PULSE[89] | Decimal point flashingNight mode is active. (The manual does not give the colour.) Eco/night symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Pego ECP200 EXPERT PULSE[89] | Icon AUX onAuxiliary relay is on (when AU1 is set to ±2 or ±3). (The manual does not give the colour.) Auxiliary output symbol: red steady |
| Secop SLV controller 105N46xx[81] | LED Service onController is in service mode/service level. (The manual does not give the colour.) Service symbol: red steady |
| LG Multi V 5 VRF outdoor units[77] | Main PCB 7-segment LED shows 88Auto addressing or auto pipe detection is running. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | LED functions lock onKeypad/functions are locked against changes. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | LED temperature unit onShows the selected temperature unit. (The manual does not give the colour.) Symbol: red steady |
| Full Gauge MT-512E Log[121] | LED functions lockdown onFunctions are locked against changes. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Full Gauge MT-512E Log[121] | LED temperature unit onShows the selected temperature unit. (The manual does not give the colour.) Symbol: red steady |
| Goodman DX20VC inverter condensing unit[105] | Red communications LED 2 flashesOut-of-box reset after control power-up or LEARN button pressed. Communication lamp: red ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Temperzone UC7 unit controller[101] | TZT-100 satellite dish symbolThermostat is communicating with the UC7. (The manual does not give the colour.) Communication lamp: white steady |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | LED on-line (green) offNo network attached. Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | ECO indicator onEnergy-saving (ECO) mode is active. (The manual does not give the colour.) Eco/night symbol: red steady |
| Dixell XR/XW (True cabinets)[145] | Icon compressor (snowflake) flashingSet point/programming mode is open. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Taylor frozen beverage freezers C300, C302, C303/C314, 345/346/349/355[149] | Product light flashingProduct not at serving viscosity (initial freeze-down, defrost or power-saver mode). (The manual does not give the colour.) Light symbol: white ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Taylor 736 soft serve freezer[153] | Draw handle icon in lower positionDraw valve is open or not fully closed. (The manual does not give the colour.) Symbol: white steady |
| Taylor 736 soft serve freezer[153] | Padlock iconKeypad is locked. (The manual does not give the colour.) Setup/programming symbol: white steady |
| Taylor 736 soft serve freezer[153] | HEAT button litHeat treatment cycle is running; do not draw product or disassemble. (The manual does not give the colour.) Heating symbol: white steady |
| Taylor 736 soft serve freezer[153] | WASH button litWash mode: beater motor running. (The manual does not give the colour.) Symbol: white steady |
| Taylor R200 fry dispenser[157] | Load size LED onShows the basket load size currently selected; drum turns until target weight is reached. (The manual does not give the colour.) Symbol: red steady |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | Icon lights onCase lights are on. (The manual does not give the colour.) Light symbol: red steady |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | Icon alarms log onAlarms have been logged; press to open the log. (The manual does not give the colour.) Alarm symbol: red steady |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | Icon AUX onAuxiliary output is active. (The manual does not give the colour.) Auxiliary output symbol: red steady |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | Icon clock onTime scheduler is active. (The manual does not give the colour.) Clock symbol: red steady |
| BAC Vertex evaporative condenser (Ziehl-Abegg ECblue EC fans)[173] | Panel OVERRIDE light (amber) onOverride switch is ON: fans follow the control signal despite the alarm. Symbol: orange steady |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | D501 (red) flashing every 5 sDISP mode is active. Setup/programming symbol: red ● · 5 s on, 5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | D501 (red) flashing every 1 sFunction select (EEPROM) setting in progress. Setup/programming symbol: red ● · 1 s on, 1 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | D503 (yellow) onMain bus communication with the central controller (about 5 s). Communication lamp: yellow steady |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | D504 (green) flashingSub bus communication with the remote controller or between group master and follower units. Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | Operation lamp (green) off during self-cleanSelf-clean is running after cooling; operation lamp goes off though the fan still runs. Symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Running lamp 1 + timer onIndoor units on a multi system ask for conflicting modes (mode conflict). (The manual does not give the colour.) Symbol: green ● → orange ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Display CLFilter cleaning reminder (15 s at power-on) or active clean running. (The manual does not give the colour.) Service symbol: white steady |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Display FP8 °C heating (frost protection) mode. (The manual does not give the colour.) Heating symbol: white steady |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Display FCForced cooling mode. (The manual does not give the colour.) Compressor symbol: white steady |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Display APWi-Fi connection in AP mode. (The manual does not give the colour.) Communication lamp: white steady |
| AHT electronic controller (plug-in cases, standard)[82] | Display --- briefly, then temperatureManual defrost refused: the 24-hour defrost block is active. (The manual does not give the colour.) Defrost symbol: red steady |
| AHT electronic controller (plug-in cases, standard)[82] | Display StP / A1-A4The set application (A1-A4) is being shown or changed. (The manual does not give the colour.) Setup/programming symbol: red steady |
| AHT electronic controller (plug-in cases, standard)[82] | Display AdrBus address setting mode. (The manual does not give the colour.) Setup/programming symbol: red steady |
| AHT electronic controller (plug-in cases, standard)[82] | Display tstSECOP controller electronics in test mode. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | LED energy optimizationEnergy optimisation (night setback / eco) is active. (The manual does not give the colour.) Eco/night symbol: red steady |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | Display ALAThe alarm button was pressed; the first alarm code follows. (The manual does not give the colour.) Alarm symbol: red steady |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | Display LocThe keypad is locked; hold up and down arrows 3 s to unlock. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | Display UnLThe keypad has been unlocked. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | Display PSA password is needed to enter the menu. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | Display FanAppliance cleaning started: only the fans are running. (The manual does not give the colour.) Fan symbol: red steady |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | Display OFFCleaning mode active (appliance can be cleaned) or the main switch is set to off. (The manual does not give the colour.) Power lamp: red steady |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | Display SErThe main switch is set to service / manual operation. (The manual does not give the colour.) Service symbol: red steady |
| Danfoss AK-PC 782A/782B[38] | LED Status quick flashAnswer received from the network gateway after network installation (lasts up to 10 min). (The manual does not give the colour.) Communication lamp: green flashing fast |
| Danfoss AK-PC 782A/782B[38] | LED Service ToolCommunication with the AK-ST 500 service tool. (The manual does not give the colour.) Communication lamp: green steady |
| Danfoss AK-PC 782A/782B[38] | LED I/O ExtensionCommunication with the AK-CM 102 module. (The manual does not give the colour.) Communication lamp: green steady |
| Danfoss AK-PC 782A/782B[38] | LED LANCommunication on the IP network. (The manual does not give the colour.) Communication lamp: green steady |
| Danfoss AK-PC 782A/782B[38] | LED DisplayCommunication with the display on the RJ11 plug. (The manual does not give the colour.) Communication lamp: green steady |
| Danfoss AK-PC 782A/782B[38] | LED Service PinThe Service Pin switch has been pressed (network address sent). (The manual does not give the colour.) Setup/programming symbol: green steady |
| Danfoss AK-PC 782A/782B[38] | LED Alarm steadyAn active alarm has been acknowledged. (The manual does not give the colour.) Alarm muted symbol: red steady |
| Danfoss AK-PC 782A/782B[38] | AK-XM 204B LED override onThe relay is overridden by its manual switch (ON or OFF position). (The manual does not give the colour.) Setup/programming symbol: green steady |
| BAC TrilliumSeries adiabatic cooler TRF[174] | HMI fan dot orangeFan status Manual: the fan is in manual mode. Setup/programming symbol: orange steady |
| BAC TrilliumSeries adiabatic cooler TRF[174] | Message Cycle of Concentration DrainThe sump is being drained to flush out minerals. (The manual does not give the colour.) Water symbol: white steady |
| BAC TrilliumSeries adiabatic cooler TRF[174] | Message Water Usage DisabledThe unit is not allowed to enter adiabatic (wet) operation. (The manual does not give the colour.) Water symbol: white steady |
| BAC TrilliumSeries adiabatic cooler TRF[174] | Message Night Quiet Mode ActiveNight quiet mode is active (fan speed limited). (The manual does not give the colour.) Eco/night symbol: white steady |
| BAC TrilliumSeries adiabatic cooler TRF[174] | Message Night Dry Mode ActiveNight dry mode is active. (The manual does not give the colour.) Eco/night symbol: white steady |
| BAC TrilliumSeries adiabatic cooler TRF[174] | Message Schedule Dry Mode ActiveScheduled dry mode is active. (The manual does not give the colour.) Eco/night symbol: white steady |
| BAC TrilliumSeries adiabatic cooler TRF[174] | Message Emergency Mode ActiveEmergency mode: fan speed is fixed at a preset level instead of PLC control. (The manual does not give the colour.) Fan symbol: white steady |
| Heatcraft Beacon II[30] | Display tStTest mode is active. Setup/programming symbol: red steady |
| Heatcraft Beacon II[30] | Display SErService mode: the service switch in the condensing unit has shut the system off. Service symbol: red steady |
| Heatcraft Beacon II[30] | Display LocThe board is locked; settings cannot be changed. Setup/programming symbol: red steady |
| Heatcraft Beacon II[30] | Display UnLThe board settings have been unlocked. Setup/programming symbol: red steady |
| Copeland PerformanceAlert diagnostic module[62] | LED yellow code after power-upFor one minute after power-up the module repeats the last alert code from before the power loss. Alarm symbol: yellow ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland EXD-SH1/2[26] | LED instant values modeManual instant-value display mode is active. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Danfoss VLT HVAC Basic Drive FC 101[70] | LED Com. yellow flashingFieldbus communication is taking place. Communication lamp: yellow ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss VLT HVAC Basic Drive FC 101[70] | LED above Hand OnThe drive is in hand (local) mode, controlled from the keypad. (The manual does not give the colour.) Setup/programming symbol: green steady |
| Carel Heos[18] | Icon lightMain screen: the cabinet light output is on. (The manual does not give the colour.) Light symbol: white steady |
| Carel Heos[18] | Icon continuous cycleMain screen: continuous cycle (forced cooling) is active. (The manual does not give the colour.) Compressor symbol: white steady |
| Carel Heos[18] | Icon anti-sweat heatersMain screen: the anti-sweat (rail) heaters are on. (The manual does not give the colour.) Heating symbol: white steady |
| Carel Heos[18] | Alarm LED red steadyThe alarm has been seen and the buzzer muted, or an auto-reset alarm is still shown; check the alarm list and reset. Alarm muted symbol: red steady |
| Carel Heos[18] | Power+ LED DATA yellowSerial communication with the Power+ drive is active. Communication lamp: yellow steady |
| Krack microchannel air-cooled condenser (controller and KB fan drive)[106] | Controller bus LED offSA bus, FC bus or Modbus LED off: no data is being sent on that bus. Communication lamp: green ● · 1 s on, 1 s off |
| LAE AT1-5/AT2-5[166] | Indicator auxiliary outputThe AUX output is on (defrost, light, alarm or on/stand-by, as set by OAU). (The manual does not give the colour.) Auxiliary output symbol: red steady |
| LAE AT1-5/AT2-5[166] | Display LOCKeypad lock setting in the info menu (YES = buttons locked). (The manual does not give the colour.) Setup/programming symbol: red steady |
| LAE AR2/BR1/BIT25 and BR+/CD25/TM (True cabinets)[146] | Icon 2nd parameter setThe second parameter set (e.g. a different setpoint) is active. (The manual does not give the colour.) Eco/night symbol: red steady |
| LAE AR2/BR1/BIT25 and BR+/CD25/TM (True cabinets)[146] | Display LocKeypad lock menu; YES means locked. (The manual does not give the colour.) Setup/programming symbol: red steady |
| LAE AR2/BR1/BIT25 and BR+/CD25/TM (True cabinets)[146] | Display inF flashingBR+/CD25/TM: entering the info menu. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | × on group icon (status area)MJ-310E: operation from the local remote controller is prohibited. (The manual does not give the colour.) Setup/programming symbol: white steady |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | Filter in yellow frameMJ-310E: filter sign, the filter needs cleaning (shown in the filter reset view). Service symbol: yellow steady |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | Operation mode flashing, red backgroundMJ-310E: the indoor unit is in operation-prohibited state (mode conflict) and stays stopped; change the operation mode to clear it. Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | Schedule mark top leftMJ-310E: a schedule is set for the group. (The manual does not give the colour.) Symbol: white steady |
| Full Gauge MT-514E Faston[122] | LED functions lockFunctions (keypad changes) are locked. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Full Gauge MT-514E Faston[122] | Display inibThe alarm buzzer has been silenced. (The manual does not give the colour.) Alarm muted symbol: red steady |
| Full Gauge MT-514E Faston[122] | Display OpEnThe door is open. (The manual does not give the colour.) Door symbol: red steady |
| Full Gauge MT-514E Faston[122] | Display LOC, OnFunctions have been locked. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Full Gauge MT-514E Faston[122] | Display LOC, OFFFunctions have been unlocked. (The manual does not give the colour.) Setup/programming symbol: red steady |
| NIBE F1255 ground source heat pump[78] | Board LED Com green flashingIrregular flashing: communication is taking place. Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| NIBE F1255 ground source heat pump[78] | Comm board LED COM green flashingCommunication with the inverter is taking place. Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss Optyma iCO2[46] | Display S25Manual mode (r12 = -1). Setup/programming symbol: green steady |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | LED light onThe cold room light is on. (The manual does not give the colour.) Light symbol: red steady |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | LED light flashingThe door switch has been activated (door open). (The manual does not give the colour.) Door symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | LED auxiliary onThe AUX relay is being called. (The manual does not give the colour.) Auxiliary output symbol: red steady |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | Decimal point flashingNight mode is active. (The manual does not give the colour.) Eco/night symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | All LEDs on at power-upLamp test for a few seconds after switching on, with a beep. (The manual does not give the colour.) Symbol: red steady |
| Carel pRack pR300[22] | Terminal LED red steadyAlarms are still present but have been acknowledged; check the alarm list. Alarm muted symbol: red steady |
| RDM Mercury AC and roof top unit controllers[130] | LED timer onThe 7-day timer has the unit switched on. (The manual does not give the colour.) Clock symbol: red steady |
| RDM Mercury AC and roof top unit controllers[130] | LED on-line offNo network is attached. (The manual does not give the colour.) Communication lamp: red off (dark) |
| RDM Mercury AC and roof top unit controllers[130] | LED on-line flashingThe controller is trying to log on to the network. (The manual does not give the colour.) Communication lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM Mercury AC and roof top unit controllers[130] | LED on-line steadyThe controller is on-line on the network. (The manual does not give the colour.) Communication lamp: red steady |
| RDM Mercury AC and roof top unit controllers[130] | LED HACCP onSet remotely by the network (Data Builder HACCP command). (The manual does not give the colour.) HACCP symbol: red steady |
| RDM ML Controller case controller[134] | LED lightsThe case lights are on. (The manual does not give the colour.) Light symbol: red steady |
| RDM ML Controller case controller[134] | LED network offNo network is attached. Communication lamp: green off (dark) |
| RDM ML Controller case controller[134] | LED network flashingThe controller is trying to log on to the network. Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM ML Controller case controller[134] | LED network steadyThe controller is on-line. Communication lamp: green steady |
| RDM ML Controller case controller[134] | LED HACCPSet on or flashing remotely by the network (HACCP command). (The manual does not give the colour.) HACCP symbol: red steady |
| Taylor R280 fry dispenser[158] | Basket size LED litShows which basket load size is selected for that side. (The manual does not give the colour.) Symbol: red steady |
| Taylor R280 fry dispenser[158] | Display [bYP] flashing bracketsBasket sensor bypass mode is being set. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Full Gauge TC-900E Log[118] | LED compressor fast flashingFast freezing mode: the cooling output runs continuously. (The manual does not give the colour.) Compressor symbol: red flashing fast |
| Full Gauge TC-900E Log[118] | LED functions lockdownFunctions (keypad changes) are locked. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Full Gauge TC-900E Log[118] | Display eCO,Running on the economic setpoint. (The manual does not give the colour.) Eco/night symbol: red steady |
| Full Gauge TC-900E Log[118] | Display OpEnThe door is open (digital input). (The manual does not give the colour.) Door symbol: red steady |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | TIMER lamp orange flashing 5 Hz (service mode)Remote-controller self-diagnosis (service mode) is running. Setup/programming symbol: orange flashing fast |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | Outdoor PCB LEDs rapid flashing 5/sLatest-error display (selected with SW81): same LED combinations as the current-error table but flashing rapidly; shows the last error that stopped the compressor. Alarm symbol: yellow flashing fast |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | Symbol noise reductionRunning in reduced-noise mode. (The manual does not give the colour.) Fan symbol: white steady |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | Symbol eco modeEnergy-saving hot water mode. (The manual does not give the colour.) Eco/night symbol: white steady |
| Dixell XM669K/XM679K[50] | Icon light onThe light relay is on. (The manual does not give the colour.) Light symbol: red steady |
| Dixell XM669K/XM679K[50] | Icon AUX onThe auxiliary relay is on. (The manual does not give the colour.) Auxiliary output symbol: red steady |
| Dixell XM669K/XM679K[50] | Icon energy savingEnergy saving is active. (The manual does not give the colour.) Eco/night symbol: red steady |
| Dixell XM669K/XM679K[50] | Icon multimasterMultimaster (SEC) is enabled: the keyboard can command other boards over the LAN. (The manual does not give the colour.) Communication lamp: red steady |
| Dixell XM669K/XM679K[50] | Icon clockTime or clock value shown. (The manual does not give the colour.) Clock symbol: red steady |
| Dixell XM669K/XM679K[50] | Units °C/bar blinkingProgramming mode. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XM669K/XM679K[50] | Board LED green onThe LAN connection between boards is working. Communication lamp: green steady |
| Dixell XM669K/XM679K[50] | Display PonKeyboard unlocked. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Dixell XM669K/XM679K[50] | Display PoFKeyboard locked. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Dixell XM669K/XM679K[50] | Display rStAlarm reset: alarm output switched off. (The manual does not give the colour.) Alarm muted symbol: red steady |
| Dixell XM669K/XM679K[50] | Display noP / nPNot present in the configuration. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Dixell XM669K/XM679K[50] | Display nAValue not available. (The manual does not give the colour.) Symbol: red steady |
| Dixell XR70CX[54] | LED continuous cycle onContinuous (fast pull-down) cycle is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XR70CX[54] | LED energy saving onEnergy saving is active. (The manual does not give the colour.) Eco/night symbol: red steady |
| Dixell XR70CX[54] | LED light onThe light output is on. (The manual does not give the colour.) Light symbol: red steady |
| Dixell XR70CX[54] | LED aux onThe auxiliary relay is on. (The manual does not give the colour.) Auxiliary output symbol: red steady |
| Dixell XR70CX[54] | LED °C/°F flashingProgramming mode. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XR70CX[54] | Display PonKeyboard unlocked. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Dixell XR70CX[54] | Display PoFKeyboard locked. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Dixell XR70CX[54] | Display noPNo parameter in Pr1, or the selected probe is not enabled. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Carel ir33[11] | Icon AUX steadyAuxiliary output configured as AUX is on. (The manual does not give the colour.) Auxiliary output symbol: red steady |
| Carel ir33[11] | Icon AUX flashingAnti-sweat heater function is active. (The manual does not give the colour.) Auxiliary output symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33[11] | Icon clock steadyAt least one timed defrost is programmed; at power-up it lights briefly if a real-time clock is fitted. (The manual does not give the colour.) Clock symbol: red steady |
| Carel ir33[11] | Icon light steadyAuxiliary output configured as LIGHT is on. (The manual does not give the colour.) Light symbol: red steady |
| Carel ir33[11] | Icon light flashingAnti-sweat heater function is active (not in firmware 3.6). (The manual does not give the colour.) Light symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33[11] | Icon HACCP steadyHACCP monitoring is enabled. (The manual does not give the colour.) HACCP symbol: red steady |
| Carel ir33 universale[19] | Icon clock steady (start-up)Shown at power-up when a real-time clock is fitted. (The manual does not give the colour.) Clock symbol: red steady |
| Carel ir33 universale[19] | Icon clock flashingAn operating cycle (CL) is running, or a clock alarm is present; check the display for a code. (The manual does not give the colour.) Clock symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33 universale[19] | Icon reverse steadyAt least one relay working in reverse (heating-type) mode is active. (The manual does not give the colour.) Heating symbol: red steady |
| Carel ir33 universale[19] | Icon reverse flashingReverse-mode PWM or 0-10 V outputs are in use. (The manual does not give the colour.) Heating symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33 universale[19] | Icon direct steadyAt least one relay working in direct (cooling-type) mode is active. (The manual does not give the colour.) Symbol: red steady |
| Carel ir33 universale[19] | Icon direct flashingDirect-mode PWM or 0-10 V outputs are in use. (The manual does not give the colour.) Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33 universale[19] | Icon TUNING flashingAuto-Tuning is enabled and running. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Sanhua SEC60x[31] | LED manual mode flashingValve is in manual mode. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Sanhua SEC60x[31] | LED TX/RX flashingData communication is taking place. (The manual does not give the colour.) Communication lamp: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Sanhua SEC60x[31] | All left-side LEDs flashingManual valve-opening mode set by DIP switch; valve opening follows the keys. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-CC55 Water Loop[35] | Display icon eco steadyEnergy optimisation is active. (The manual does not give the colour.) Eco/night symbol: red steady |
| Danfoss AK-CC55 Water Loop[35] | Display FanAppliance cleaning started; only the fans run. (The manual does not give the colour.) Fan symbol: red steady |
| Danfoss AK-CC55 Water Loop[35] | Display OFFCleaning mode active (appliance can be cleaned) or main switch set to off. (The manual does not give the colour.) Power lamp: red steady |
| Danfoss AK-CC55 Water Loop[35] | Display SErMain switch set to service/manual operation. (The manual does not give the colour.) Service symbol: red steady |
| Danfoss AK-CC55 Water Loop[35] | Bluetooth light flashingBluetooth pairing active; the display shows the controller address. (The manual does not give the colour.) Communication lamp: blue ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss Optyma control AK-RC 113[39] | Icon door/light steadyRoom light is on. (The manual does not give the colour.) Light symbol: red steady |
| Danfoss Optyma control AK-RC 113[39] | Icon door/light flashingDoor switch is enabled and the room light is on. (The manual does not give the colour.) Door symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss Optyma control AK-RC 113[39] | Icon AUX steadyAuxiliary relay is called for. (The manual does not give the colour.) Auxiliary output symbol: red steady |
| Danfoss Optyma control AK-RC 113[39] | Decimal point flashingNight (energy-saving) mode is active. (The manual does not give the colour.) Eco/night symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss EKE 1A/1B/1C/1D[43] | Status LED green flashingData transmission or initialisation. Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss EKE 1A/1B/1C/1D[43] | Valve LED red flashingValve is closing. Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss EKE 1A/1B/1C/1D[43] | Valve LED red steadyValve is fully closed. Symbol: red steady |
| Danfoss EKE 1A/1B/1C/1D[43] | Valve LED green flashingValve is opening. Symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss EKE 1A/1B/1C/1D[43] | Valve LED green steadyValve is fully open. Symbol: green steady |
| Danfoss AK-RC 251[47] | Icon door steadyCold room door is open. (The manual does not give the colour.) Door symbol: red steady |
| Danfoss AK-RC 251[47] | Icon light steadyCold room light is on. (The manual does not give the colour.) Light symbol: red steady |
| Danfoss AK-RC 251[47] | Icon alarm muted steadyAn alarm is in progress but the buzzer has been muted. (The manual does not give the colour.) Alarm muted symbol: red steady |
| Danfoss AK-RC 251[47] | Icon programming steadyProgramming mode is active. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Dixell XR06CX[51] | LED °C/°F flashingProgramming mode. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XW60K/XW60L[55] | LED energy saving steadyEnergy saving is enabled. (The manual does not give the colour.) Eco/night symbol: red steady |
| Dixell XW60K/XW60L[55] | LED light steadyLight is on. (The manual does not give the colour.) Light symbol: red steady |
| Dixell XW60K/XW60L[55] | LED AUX steadyAuxiliary relay is on. (The manual does not give the colour.) Auxiliary output symbol: red steady |
| Dixell XW60K/XW60L[55] | LED °C/°F flashingProgramming phase (XW60L). (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel µC2SE for process chiller[59] | Icon chiller mode amber steadyUnit is in chiller mode. Symbol: orange steady |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | Symbol door heaterDoor heater is on. (The manual does not give the colour.) Heating symbol: red steady |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | Display ---Cooling function is switched off (manual defrost / cleaning). (The manual does not give the colour.) Power lamp: red steady |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | Display Adr alternatingBus-address setting mode; the current address alternates with Adr. (The manual does not give the colour.) Communication lamp: red steady |
| RDM DMTouch / miniDM[91] | Dongle network LEDs flashing brieflyIdentify pressed on the RS485 Adapters page. (The manual does not give the colour.) Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM DMTouch / miniDM[91] | LED red/green flashing 10 timesLED test started from the Test page. (The manual does not give the colour.) Symbol: red ●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | PCB LED D02 flashing 10 sNo DISP mode. Symbol: red ● · 5 s on, 5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | PCB LED D02 flashing 2 sFunction change (EEPROM) is being set. Setup/programming symbol: red ● · 1 s on, 1 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | PCB LED D203 on 5 sGroup header unit is communicating with the remote controller. Communication lamp: red steady |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | PCB LED D203 fast flashingCommunication between group header and follower units. Communication lamp: red flashing fast |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | PCB LED flashing (unit selected)This module is the one selected from the remote controller for a setting change. Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | Remote central control indicator flashingRemote buttons are locked by central control. (The manual does not give the colour.) Communication lamp: white ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | Remote TEST run indicatorTest run in progress. (The manual does not give the colour.) Service symbol: white steady |
| RDM Intuitive / Mercury pack and condenser controllers[131] | LED section 1 steadySection 1 pressure is being displayed. (The manual does not give the colour.) Symbol: green steady |
| RDM Intuitive / Mercury pack and condenser controllers[131] | LED section 2 steadySection 2 pressure is being displayed. (The manual does not give the colour.) Symbol: green steady |
| RDM Intuitive / Mercury pack and condenser controllers[131] | LED network offNo network attached. (The manual does not give the colour.) Communication lamp: green off (dark) |
| RDM Intuitive / Mercury pack and condenser controllers[131] | LED network flashingTrying to log on to the network. (The manual does not give the colour.) Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM Intuitive / Mercury pack and condenser controllers[131] | LED HACCP flashingSet only by a remote network command (HACCP). (The manual does not give the colour.) HACCP symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Temperzone UC6 unit controller[135] | DS1 digit bDRM2/DRM3 demand response active: reduced capacity. (The manual does not give the colour.) Symbol: red steady |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | Heat Cycle key litHeat treatment cycle is running. (The manual does not give the colour.) Heating symbol: green steady |
| Taylor heat treatment freezers C708/C716, C708 shake, C606[151] | Topping heater keys litTopping heaters are on. (The manual does not give the colour.) Heating symbol: green steady |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | STAND-BY lamp after heat treatmentHeat treatment finished; mix is kept refrigerated. (The manual does not give the colour.) Power lamp: green steady |
| Taylor Icetro ISI-271THS/SHS, ISI-300TA, ISI-301TH[155] | Supplemental cooling lamp onDuring heating the buttons can still be used while this lamp is on. (The manual does not give the colour.) Symbol: green steady |
| Dixell XR03CX/XR04CX (Hillphoenix display cases)[159] | LED °C/°F flashingProgramming mode. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland (CPC) E2 RX/BX/CX controller[163] | PIB/RS485 card LED yellow RX onData is being received on the RS485 port. Communication lamp: yellow steady |
| Copeland (CPC) E2 RX/BX/CX controller[163] | PIB/RS485 card LED red TX onData is being sent on the RS485 port. Communication lamp: red steady |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Case lights flashing 5 sWash mode is about to end; fans and cooling restart. (The manual does not give the colour.) Light symbol: white ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Pego 202BASE electronic board[167] | Decimal point flashingNight (energy-saving) mode is active. (The manual does not give the colour.) Eco/night symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Vaillant aroSTOR plus VWL B/BM 200/6, 260/6[171] | Symbol PV/Smart GridA signal from the PV system or Smart Grid has been received. (The manual does not give the colour.) Symbol: white steady |
| Vaillant aroSTOR plus VWL B/BM 200/6, 260/6[171] | Display --- flashing with d0nFactory settings have been restored. (The manual does not give the colour.) Setup/programming symbol: white ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carpigiani AES PSP[15] | Function LED onThe function next to the LED is selected. (The manual does not give the colour.) Symbol: red steady |
| Carpigiani AES PSP[15] | Display Pasto EndPasteurisation cycle completed successfully. (The manual does not give the colour.) Symbol: red steady |
| Danfoss Optyma Plus[4] | LED crankcase heater steadyLit while the crankcase heater is switched on. (The manual does not give the colour.) Heating symbol: red steady |
| Carel μC2SE[8] | LED heater steadyHeater (antifreeze/support heater) is on. Heating symbol: orange steady |
| Carel μC2SE[8] | LED chiller mode steadyUnit is operating in chiller (cooling) mode. Symbol: orange steady |
| Carel μC2SE[8] | LED chiller mode flashingChiller mode has been requested and is pending. Symbol: orange ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XR60CX[12] | LED continuous cycle steadyContinuous (fast pull-down) cycle is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XR60CX[12] | LED energy saving steadyEnergy saving mode is enabled. (The manual does not give the colour.) Eco/night symbol: red steady |
| Dixell XR60CX[12] | LED °C/°F flashingController is in programming mode. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel EVD evolution / EVD evolution twin[16] | LED NET green steadyNetwork connection to the controller is available. Communication lamp: green steady |
| Carel SmartCella / SmartCella 3PH[24] | AUX icon steadyAuxiliary output 1 or 2 is active. (The manual does not give the colour.) Auxiliary output symbol: red steady |
| Carel SmartCella / SmartCella 3PH[24] | AUX/light icon flashingAnti-sweat heater function is active. (The manual does not give the colour.) Auxiliary output symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel SmartCella / SmartCella 3PH[24] | Light icon steadyAuxiliary output configured as cold-room light is on. (The manual does not give the colour.) Light symbol: red steady |
| Carel SmartCella / SmartCella 3PH[24] | Continuous cycle icon steadyContinuous cycle function is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Carel SmartCella / SmartCella 3PH[24] | HACCP icon steadyHACCP monitoring (HA/HF) is enabled. (The manual does not give the colour.) HACCP symbol: red steady |
| Carel SmartCella / SmartCella 3PH[24] | Clock icon steadyClock function (RTC) is active. (The manual does not give the colour.) Clock symbol: red steady |
| Carel SmartCella / SmartCella 3PH[24] | Clock icon flashingClock function has been requested. (The manual does not give the colour.) Clock symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-CC 750[36] | LED Status quick flashAnswer from the gateway/system unit after network installation (lasts about 10 minutes). (The manual does not give the colour.) Communication lamp: green flashing fast |
| Danfoss AK-CC 750[36] | LED Service Tool steadyCommunication with the Service Tool PC program is active. (The manual does not give the colour.) Communication lamp: green steady |
| Danfoss AK-CC 750[36] | LED LON flashingData communication on the LON network. (The manual does not give the colour.) Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-CC 750[36] | LED Service Pin steadyService Pin switch has been activated for network installation. (The manual does not give the colour.) Setup/programming symbol: green steady |
| Dixell XC645D[48] | LED maintenance (spanner) steadyThe maintenance menu is open. (The manual does not give the colour.) Service symbol: red steady |
| Dixell XC645D[48] | LED maintenance (spanner) flashingOne or more loads have been put in maintenance status (disabled). (The manual does not give the colour.) Service symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XC645D[48] | LED alarm-log steadyAll stored alarms have been viewed. (The manual does not give the colour.) Alarm symbol: red steady |
| Dixell XC645D[48] | LED energy saving steadyEnergy saving is active. (The manual does not give the colour.) Eco/night symbol: red steady |
| Dixell XR35CX[52] | LED continuous cycle steadyContinuous (fast pull-down) cycle is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XR35CX[52] | LED energy saving steadyEnergy saving is enabled. (The manual does not give the colour.) Eco/night symbol: red steady |
| Dixell XR35CX[52] | LED light steadyLight output is on. (The manual does not give the colour.) Light symbol: red steady |
| Dixell XR35CX[52] | LED auxiliary steadyAuxiliary relay is on. (The manual does not give the colour.) Auxiliary output symbol: red steady |
| Dixell XR35CX[52] | LED °C/°F flashingController is in programming mode. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XWi70K[56] | LED fan flashingProgramming mode (flashes together with the compressor LED). (The manual does not give the colour.) Fan symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XWi70K[56] | LED pull down steadyPull-down (continuous cycle) is running. (The manual does not give the colour.) Compressor symbol: red steady |
| Dixell XWi70K[56] | LED energy saving steadyEnergy saving is enabled. (The manual does not give the colour.) Eco/night symbol: red steady |
| Dixell XWi70K[56] | LED light steadyLight output is on. (The manual does not give the colour.) Light symbol: red steady |
| Dixell XWi70K[56] | LED auxiliary steadyAuxiliary output is on. (The manual does not give the colour.) Auxiliary output symbol: red steady |
| Carel µChiller[60] | System pump icon flashingSystem pump is in manual operation. (The manual does not give the colour.) Pump symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel µChiller[60] | Source pump/fan icon flashingSource pump/fan is in manual operation. (The manual does not give the colour.) Fan symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel µChiller[60] | Compressor icon flashingCompressor in manual operation (with electronic expansion valve). (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel µChiller[60] | Frost protection heater icon steadyFrost-protection heater is on. (The manual does not give the colour.) Heating symbol: red steady |
| Carel µChiller[60] | Heating mode icon steadyUnit is in heating mode. (The manual does not give the colour.) Heating symbol: red steady |
| Carel µChiller[60] | Cooling mode icon steadyUnit is in cooling mode. (The manual does not give the colour.) Symbol: red steady |
| Carel µChiller[60] | Free cooling icon steadyFree cooling is active. (The manual does not give the colour.) Symbol: red steady |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | LED yellow fast flashingUnit is in a special mode (e.g. service/test). Setup/programming symbol: yellow flashing fast |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | Relay module LEDsEach relay LED follows its relay coil (off = coil de-energised); meaning depends on energised/de-energised setting. (The manual does not give the colour.) Symbol: green steady |
| AHT GD-Cooler (GD-XLS, GD-XL)[84] | LED symbol °C/°F flashingSetpoint is being changed. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM Mercury 3 Twin Coil[92] | LED on-line offNo network attached. Communication lamp: green off (dark) |
| RDM Mercury 3 Twin Coil[92] | LED on-line flashingController is trying to log on to the network. Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM Mercury 3 Twin Coil[92] | LED on-line steadyController is on-line on the network. Communication lamp: green steady |
| RDM Mercury 3 Twin Coil[92] | LED HACCP steady/flashingHACCP LED is switched on or set flashing by the network command (site-defined meaning). (The manual does not give the colour.) HACCP symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland Electronic Unit Controller[116] | LED PSI steadyPressures are shown in psig. (The manual does not give the colour.) Symbol: red steady |
| Copeland Electronic Unit Controller[116] | LED PSI flashingController is in programming mode. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland Electronic Unit Controller[116] | LED service steadyService menu is being browsed. (The manual does not give the colour.) Service symbol: red steady |
| Copeland Electronic Unit Controller[116] | LED alarm-menu steadyThe alarm menu is being browsed. (The manual does not give the colour.) Alarm symbol: red steady |
| Full Gauge MT-512E 2HP[120] | LED heating steadyHeating output is on. (The manual does not give the colour.) Heating symbol: red steady |
| Full Gauge MT-512E 2HP[120] | LED functions lockdown steadyParameter lock (tamper-proof) is active. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | Light block all three synchronized blinkingTest run is in progress (all three lamps blink together). (The manual does not give the colour.) Setup/programming symbol: green ● → yellow ● → orange ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | LED lights steadyLights relay (relay 3) is on. (The manual does not give the colour.) Light symbol: red steady |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | LED on-line offNo network attached. Communication lamp: green off (dark) |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | LED on-line flashingController is trying to log on to the network. Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | LED on-line steadyController is on-line on the network. Communication lamp: green steady |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | LED HACCP steady/flashingHACCP LED switched on or set flashing by a network command (site-defined meaning). (The manual does not give the colour.) HACCP symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel PQ (True cabinets)[144] | 2nd parameter set icon steadyThe second parameter set is active. (The manual does not give the colour.) Symbol: red steady |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | Alarm LED flashingAlarm acknowledged/buzzer silenced; the alarm is still present until the cause clears. (The manual does not give the colour.) Alarm muted symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | Economy (reduced set) icon steadyEnergy-saving mode is on. (The manual does not give the colour.) Eco/night symbol: red steady |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | Economy (reduced set) icon flashingReduced setpoint mode is active. (The manual does not give the colour.) Eco/night symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | Economy (reduced set) icon fast flashingLevel-2 parameter menu is open. (The manual does not give the colour.) Setup/programming symbol: red flashing fast |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | AUX icon steadyAuxiliary output is active. (The manual does not give the colour.) Auxiliary output symbol: red steady |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | AUX icon flashingDeep-cooling (pull-down) cycle is active. (The manual does not give the colour.) Compressor symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Taylor soft serve and shake freezers C709/C717, C712, C713, C612[152] | Standby symbol onStandby mode is active; hopper and cylinder are kept below 4.4 °C (40 °F). (The manual does not give the colour.) Power lamp: red steady |
| Carel MPXzero (Hillphoenix display cases)[160] | Lights icon steadyCase lights are on. (The manual does not give the colour.) Light symbol: red steady |
| alpha innotec BWP 190S/260S DHW heat pump[168] | Symbol electric heater shownElectric backup heater is switched on (symbol shows ON/OFF state). (The manual does not give the colour.) Heating symbol: white steady |
| IVT AirX air-to-water heat pump[175] | 1041Power was lost during the screed drying programme; it resumes by itself unless the outage lasted longer than the battery reserve or the set maximum time. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 1041Power was lost during the screed drying programme; it resumes by itself unless the outage lasted longer than the battery reserve or the set maximum time. |
| IVT Geo 500/600 series ground source heat pump[177] | 5937Flow through PC0 is driven by another pump in the circuit that the heat pump does not control. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 1041Power was lost during the screed drying programme; it resumes by itself unless the outage lasted longer than the battery reserve or the set maximum time. |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation steady + Timer and Swing slow blinkTest run is active. (The manual does not give the colour.) Service symbol: green + red + yellow ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 9–30 (older, one red LED)[187] | LED red slow blinkA protective function is limiting operation; not a stored fault. red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 36–54 (older, one red LED)[188] | LED red slow blinkA protective function is limiting operation; not a stored fault. red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red steady + Green steadyTimer mode is set. Symbol: red + green steady |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red steady + Yellow steadyLouvre swing is on (green may be on or off). Fan symbol: red + yellow steady |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red + Green pulsingTest run is active. Service symbol: red + green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Hitachi RUA-NP4ATS…NP10ATS self-contained (packaged, ducted) air conditioners, R410A, cooling only, 1 or 2 scroll compressors (PCB display SEG1)[195] | ALShown flashing when the PCB is in alarm history mode (SW1 held for more than 3 s): each further press of SW1 shows one of the last five alarm codes; holding SW1 for more than 5 s clears the history. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | orOil recovery operation is running (every 3 h of compressor running in cooling, 8 h in heating; first time after 1 h). Normal; indoor Operation lamps flash slowly. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | PCPeak cut mode active: compressor capacity is held down to cut the power peak. Not a fault; capacity may be lower. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | LnLow noise mode active: the outdoor fan runs at limited speed. Not a fault; capacity may be lower in high ambient. |
| Fujitsu AIRSTAGE J-II VRF – indoor units (Operation/Timer/Filter lamps)[199] | Operation steady, dimmedAnti-freeze control is active: the indoor coil is protected against freezing in cooling; the lamp lights at reduced brightness. Not a fault. (The manual does not give the colour.) green steady |
| Fujitsu AIRSTAGE J-II VRF – indoor units (Operation/Timer/Filter lamps)[199] | Timer steady, dimmedA timer is set (lamp at reduced brightness). (The manual does not give the colour.) orange steady |
| Fujitsu AIRSTAGE J-II VRF – indoor units (Operation/Timer/Filter lamps)[199] | Operation + Timer flashing alternately (1 s)Power failure indication: the unit has had a power failure. Check the supply. (The manual does not give the colour.) green + orange ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu AIRSTAGE J-II VRF – indoor units (Operation/Timer/Filter lamps)[199] | Operation + Timer flashing together (1 s)Test operation is running. (The manual does not give the colour.) green + orange ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu AIRSTAGE J-II VRF – indoor units (Operation/Timer/Filter lamps)[199] | Operation + Timer + Filter flashing (1 s)Maintenance mode is active. (The manual does not give the colour.) green + orange + red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Dixell XW60K/XW60L[55] | LED fan flashingProgramming phase (the fan LED flashes while parameters are being set, per the XW60K table). Fan symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel pRack pR300[22] | Icon manual operation (main screen)Shown in the main screen status field when one or more outputs are in manual operation. (The manual does not give the colour.) Setup/programming symbol: yellow steady |
| Carel pRack pR300[22] | Icon password level (1-3 lines, menu screens)Lines in the top right corner show the access level: one for user, two for maintenance, three for manufacturer. (The manual does not give the colour.) Setup/programming symbol: yellow steady |
| RDM Intuitive / Mercury pack and condenser controllers[131] | LED HACCP steadyHACCP LED lit; it is switched on only by a remote network command from the system manager. HACCP symbol: green steady |
| LAE BR1-27/BR1-28/BR5-A/BR5-B/BD1-28/CD25[165] | Icon 2nd setpoint (II Set) steadyThe second parameter group (set II) is active, e.g. eco, night or clock-controlled operation. (The manual does not give the colour.) Eco/night symbol: red steady |
| Thermia Atella / Robust[114] | Symbol clock (tariff control)Tariff control is active. (The manual does not give the colour.) Clock symbol: yellow steady |
| Thermia Atella / Robust[114] | Symbol tank (water heater level)Shows the hot water tank temperature level while it is charged. (The manual does not give the colour.) Water symbol: yellow steady |
| Thermia Atella / Robust[114] | Symbol tank with lightningPeak heating charge (anti-legionella) is in progress. (The manual does not give the colour.) Heating symbol: yellow steady |
| Carel MasterCella[7] | AUX icon steadyAuxiliary output set as AUX is switched on. (The manual does not give the colour.) Auxiliary output symbol: red steady |
| Carel MasterCella[7] | AUX icon flashingAnti-sweat heater function is active. (The manual does not give the colour.) Auxiliary output symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel MasterCella[7] | Clock icon steadyAt least one timed defrost is programmed; at power-up it lights briefly when a real-time clock is fitted. (The manual does not give the colour.) Clock symbol: red steady |
| Carel MasterCella[7] | Light icon steadyAuxiliary output set as LIGHT is switched on. (The manual does not give the colour.) Light symbol: red steady |
| Carel MasterCella[7] | Light icon flashingAnti-sweat heater function is active (not in firmware 3.6). (The manual does not give the colour.) Light symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel MasterCella[7] | HACCP icon steadyHACCP function is enabled. (The manual does not give the colour.) HACCP symbol: red steady |
| Carel ir33 universale[19] | Icon TUNING steadyAuto-tuning function is running. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Carel pRack pR300T (transcritical CO2)[23] | Main screen manual operation signal (field 4)The main screen shows a signal that one or more outputs are in manual operation. (The manual does not give the colour.) Setup/programming symbol: white steady |
| Danfoss AK-PC 781A[37] | Extension module (AK-XM 204B/205B) override LED onA relay on the module is overridden by hand; off means no override. (The manual does not give the colour.) Symbol: green steady |
| RDM Mercury 3 Twin Coil[92] | LED HACCP steadyHACCP LED switched on by a network command from the data manager. (The manual does not give the colour.) HACCP symbol: red steady |
| RDM Mercury 3 Twin Coil[92] | Key backlights flashingKey backlights set to flash by a network command from the data manager. (The manual does not give the colour.) Symbol: white ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | LED HACCP steadyHACCP LED switched on by a network command from the data manager. (The manual does not give the colour.) HACCP symbol: red steady |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | Icon lights flashingLights are off but can be switched on from the keypad. (The manual does not give the colour.) Light symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel μC2SE[8] | LED heat pump mode steadyThe unit is running in heat pump mode (P6=0). Symbol: orange steady |
| Carel μC2SE[8] | LED heat pump mode flashingHeat pump mode has been requested but is not yet active (P6=0). Symbol: orange ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XR60CX[12] | LED °C/°F steadyShows the unit of the displayed temperature. (The manual does not give the colour.) Symbol: red steady |
| Carel ir33+ VCC[20] | AUX icon steadyAuxiliary output 1 or 2 is active. (The manual does not give the colour.) Auxiliary output symbol: red steady |
| Carel ir33+ VCC[20] | AUX icon flashingThe anti-sweat heater function is active. (The manual does not give the colour.) Auxiliary output symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33+ VCC[20] | Clock icon steadyA timed defrost is set; with a real-time clock fitted it also shows briefly at start-up. (The manual does not give the colour.) Clock symbol: red steady |
| Carel ir33+ VCC[20] | Light icon steadyAn auxiliary output set as light is on. (The manual does not give the colour.) Light symbol: red steady |
| Carel ir33+ VCC[20] | Light icon flashingThe anti-sweat heater function is active. (The manual does not give the colour.) Light symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33+ VCC[20] | HACCP icon steadyThe HACCP function is enabled. (The manual does not give the colour.) HACCP symbol: red steady |
| Carel SmartCella / SmartCella 3PH[24] | Light icon flashingThe anti-sweat heater function is active. (The manual does not give the colour.) Light symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Störk-Tronic ST121 / ST501 / ST551[93] | ST501 LED5 on (default)With factory settings LED5 shows that parameter set 1 is active. (The manual does not give the colour.) Symbol: red steady |
| Störk-Tronic ST121 / ST501 / ST551[93] | ST501 LED6 on (default)With factory settings LED6 shows that parameter set 2 is active. (The manual does not give the colour.) Symbol: red steady |
| Full Gauge MT-512E 2HP[120] | LED defrost flashingFlashes while the manual defrost item is selected in the quick menu, before it is confirmed. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Full Gauge MT-512E 2HP[120] | LED temperature unit steadyShows the unit of the displayed temperature. (The manual does not give the colour.) Symbol: red steady |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | LED service steady (Control Thermostat)The controller is in the additional parameter setting mode. (The manual does not give the colour.) Service symbol: red steady |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | LED HACCP steady (remote command)Switched on by a remote command from a Data Builder program. (The manual does not give the colour.) HACCP symbol: red steady |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | LED HACCP flashing (remote command)Set to flash by a remote command from a Data Builder program. (The manual does not give the colour.) HACCP symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | LED lights steady (5 Channel Thermostat)The timer is in its on period. (The manual does not give the colour.) Light symbol: red steady |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | °C / °F icon steadyShows which temperature unit is set. (The manual does not give the colour.) Symbol: red steady |
| Pego 202BASE electronic board[167] | LED room light steadyThe cold room light is on. (The manual does not give the colour.) Light symbol: red steady |
| Pego 202BASE electronic board[167] | LED room light flashingThe door switch is activated. (The manual does not give the colour.) Door symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Pego 202BASE electronic board[167] | LED AUX steadyThe auxiliary relay is called (AU1/AU2 = +/-2 or +/-3). (The manual does not give the colour.) Auxiliary output symbol: red steady |
| Dixell XW270L/XW271L[9] | LED fan flashingFlashes together with the compressor LED while in programming mode. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XW270L/XW271L[9] | SET button LED flashingThe set point is shown and can be changed. (The manual does not give the colour.) Setup/programming symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XW270L/XW271L[9] | SET button LED fast flashingEnergy saving mode is active. (The manual does not give the colour.) Eco/night symbol: red flashing fast |
| Dixell XW270L/XW271L[9] | ENERGY SAVING button LED onEnergy saving mode is active. (The manual does not give the colour.) Eco/night symbol: red steady |
| Dixell XW270L/XW271L[9] | LIGHT button LED onThe cabinet/room light output is on. (The manual does not give the colour.) Light symbol: red steady |
| Dixell XW270L/XW271L[9] | AUX button LED on (XW270L)XW270L only: the auxiliary output is on. (The manual does not give the colour.) Auxiliary output symbol: red steady |
| Dixell XW270L/XW271L[9] | HEATER button LED on (XW271L)XW271L only: the anti-condensing heater is on. (The manual does not give the colour.) Heating symbol: red steady |
| Eliwell ID 974[13] | LED alarm flashingThe alarm has been acknowledged and the buzzer silenced; the alarm is still present. (The manual does not give the colour.) Alarm muted symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Eliwell ID 974[13] | LED economy (reduced set) flashing (IDPlus)IDPlus: the reduced (economy) set point is active. (The manual does not give the colour.) Eco/night symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Eliwell ID 974[13] | LED AUX on (IDPlus)IDPlus: auxiliary output indication; its meaning depends on the model. (The manual does not give the colour.) Auxiliary output symbol: red steady |
| Eliwell ID 974[13] | LED °C on (IDPlus)IDPlus: temperatures are shown in °C (dro = 0). (The manual does not give the colour.) Symbol: red steady |
| Eliwell ID 974[13] | LED °F on (IDPlus)IDPlus: temperatures are shown in °F (dro = 1). (The manual does not give the colour.) Symbol: red steady |
| Carel MPXone[21] | UP/DOWN button LED onScrolling menus, parameters or direct access functions; a key is usable only when lit. (The manual does not give the colour.) Setup/programming symbol: red steady |
| Carel µRack[25] | Icon BAR onValues are shown in bar. (The manual does not give the colour.) Symbol: red steady |
| Carel µRack[25] | Icon °C onValues are shown in °C. (The manual does not give the colour.) Symbol: red steady |
| Carel µRack[25] | Icon suction probe onThe display shows the suction probe value. (The manual does not give the colour.) Symbol: red steady |
| Carel µRack[25] | Icon discharge probe onThe display shows the discharge probe value. (The manual does not give the colour.) Symbol: red steady |
| Sanhua SEC60x[31] | LED SH onThe display shows superheat. (The manual does not give the colour.) Symbol: red steady |
| Sanhua SEC60x[31] | LED PRESS onThe display shows pressure. (The manual does not give the colour.) Symbol: red steady |
| Sanhua SEC60x[31] | LED OPEN onThe display shows the valve opening in %. (The manual does not give the colour.) Symbol: red steady |
| Sanhua SEC60x[31] | LED TEMP onThe display shows a temperature. (The manual does not give the colour.) Symbol: red steady |
| Sanhua SEC60x[31] | LED °C/bar onShows the unit of the displayed temperature or pressure. (The manual does not give the colour.) Symbol: red steady |
| Dixell XM669K/XM679K[50] | Units °C/bar/time onShows the unit of the displayed value. (The manual does not give the colour.) Symbol: red steady |
| Dixell XR70CX[54] | LED °C/°F onShows the selected temperature unit. (The manual does not give the colour.) Symbol: red steady |
| Dixell XR03CX/XR04CX (Hillphoenix display cases)[159] | LED °C/°F onShows the selected temperature unit. (The manual does not give the colour.) Symbol: red steady |
| Full Gauge MT-512E Log[121] | LED defrost flashing (quick access menu)The defrost command is selected in the quick access menu; press to switch defrost on or off. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| NIBE F1255 ground source heat pump[78] | MODBUS 40 LED COM1 flashingMODBUS 40 accessory is communicating with the heat pump. (The manual does not give the colour.) Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| NIBE F1255 ground source heat pump[78] | SMS 40 LED COM1 flashingSMS 40 is communicating with the heat pump (also at start-up). (The manual does not give the colour.) Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| NIBE F1255 ground source heat pump[78] | SMS 40 LED LEV steadySMS 40 GSM signal is OK. (The manual does not give the colour.) Communication lamp: green steady |
| NIBE F1255 ground source heat pump[78] | SMS 40 LED COM2 flashingSMS 40 is communicating with its GSM modem. (The manual does not give the colour.) Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| NIBE F1255 ground source heat pump[78] | SMS 40 LED SYNC flashingSMS 40 is sending or receiving a text message. (The manual does not give the colour.) Communication lamp: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM Mercury AC and roof top unit controllers[130] | LED HACCP flashingHACCP LED set to flash by a remote command from the system manager. (The manual does not give the colour.) HACCP symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM Mercury AC and roof top unit controllers[130] | Function key backlights flashingKey backlights set to flash by a remote command; keys normally light when pressed and go dark after 20 s. (The manual does not give the colour.) Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM ML Controller case controller[134] | LED HACCP flashingHACCP LED set to flash by a remote command from the system manager. (The manual does not give the colour.) HACCP symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Header icon single userOne user is logged in to the E2. (The manual does not give the colour.) Setup/programming symbol: white steady |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Header icon multiple usersSeveral users are logged in to the E2. (The manual does not give the colour.) Setup/programming symbol: white steady |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Header icon terminal modeTerminal mode is in use. (The manual does not give the colour.) Communication lamp: white steady |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Header icon EthernetThe E2 is connected to Ethernet. (The manual does not give the colour.) Communication lamp: white steady |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Header icon wait/busyThe system is busy; wait. (The manual does not give the colour.) Symbol: white steady |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Header icon disk activityThe E2 is reading or saving to its memory. (The manual does not give the colour.) Symbol: white steady |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Header icon caps lockCaps lock is on. (The manual does not give the colour.) Symbol: white steady |
| Evco EV3203[107] | LED energy saving steadyEnergy saving mode is on. (The manual does not give the colour.) Eco/night symbol: red steady |
| Evco EV3 300 series[108] | LED °C/°F steadyThe display shows a temperature in the unit of the lit LED. (The manual does not give the colour.) Symbol: red steady |
| Evco EVK214[109] | LED HACCP steadyNot all stored HACCP alarms have been viewed yet. (The manual does not give the colour.) HACCP symbol: red steady |
| Evco EVK214[109] | LED maintenance steadyCompressor maintenance is due (C10). (The manual does not give the colour.) Service symbol: red steady |
| Evco EVK214[109] | LED °C or °F blinkingEnergy saving is active (r4, i5, HE1, HE2). (The manual does not give the colour.) Eco/night symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Evco EVK214[109] | LED multifunction steady (u1 = 0, light)The cabinet light was switched on manually. (The manual does not give the colour.) Light symbol: red steady |
| Evco EVK214[109] | LED multifunction blinking (u1 = 0, light)The cabinet light was switched on remotely (i0). (The manual does not give the colour.) Light symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
The lamp gives information that is not a fault, for example communication, start-up, self-test, service or emergency mode.
Check: See the manual for the product; check communication wiring and settings when the lamp points to them.
Status: defrost or drip time
| Controller | Code |
|---|---|
| Danfoss ERC 21X[1] | Icon defrost steadyA defrost cycle is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Copeland EazyCool ZX (XCM25D)[5] | LED defrost onUnit is in defrost. (The manual does not give the colour.) Defrost symbol: red steady |
| Carel MPXone[21] | Icon defrost onDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Carel MPXone[21] | Icon defrost flashingA defrost is requested and waiting to start. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-CC 550 / 550B[33] | LED defrost onDefrost relay is on. (The manual does not give the colour.) Defrost symbol: red steady |
| Danfoss EKC 202D1[41] | LED defrost onDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Dixell XR460C[53] | Icon defrost 1 onDefrost of section 1 in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Dixell XR460C[53] | Icon defrost 1 flashingDrip time running for section 1. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XR460C[53] | Icon defrost 2 onDefrost of section 2 in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Dixell XR460C[53] | Icon fan flashingDrip time in progress (fans held off after defrost). (The manual does not give the colour.) Fan symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Pego ECP200 EXPERT PULSE[89] | Icon fans flashingFans paused after defrost (time F5). (The manual does not give the colour.) Fan symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Pego ECP200 EXPERT PULSE[89] | Icon defrost onDefrost is called/in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Pego ECP200 EXPERT PULSE[89] | Icon defrost flashingDrip time after defrost (time d7); compressor and fans stopped. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| AHT plug-in cases with Danfoss controller (Paris, Ibiza, Malta, Manhattan)[85] | Defrost LED symbol onA manually started defrost is in progress (display shows dEF). (The manual does not give the colour.) Defrost symbol: red steady |
| Secop SLV controller 105N46xx[81] | LED Defrosting onDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Störk-Tronic ST121 / ST501 / ST551[93] | LED2 on (default)Defrost of control circuit 1 is active (default U12 = 2; can be reassigned). This default applies to the ST121/ST501; on the ST551 LED2 shows a high-pressure alarm by default. Defrost symbol: red steady |
| Full Gauge TC-900E POWER / TC-900E 2HP[117] | LED defrost onDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Full Gauge MT-512E Log[121] | LED defrost onDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | LED defrost (amber) onA channel is in defrost; its alarms are inhibited during defrost and recovery. On the PR0440 the defrost LED shows the timer instead: lit = timer off (out of hours), dark = timer on. Defrost symbol: orange steady |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | Icon defrost onCabinet is in defrost. (The manual does not give the colour.) Defrost symbol: red steady |
| Dixell XR/XW (True cabinets)[145] | Icon defrost onDefrost (or reversing condenser fan) is running. (The manual does not give the colour.) Defrost symbol: red steady |
| Dixell XR/XW (True cabinets)[145] | Icon defrost flashingDrip time after defrost is in progress. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Taylor frozen beverage freezers C300, C302, C303/C314, 345/346/349/355[149] | LCD DEF flashingBarrel is in DEFROST PENDING (e.g. during beater overload recovery). (The manual does not give the colour.) Defrost symbol: white ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | Icon defrost onDefrost is active (can be stopped from the keypad). (The manual does not give the colour.) Defrost symbol: red steady |
| ActronAir DS Series and R-32 split systems (Serene DS, Aspire DS, Cascade DS, MultiElite DS, Cassette 2)[138] | Display FDefrost in progress; at power-on (15 s) it can instead be the filter replacement reminder. (The manual does not give the colour.) Defrost symbol: white steady |
| AHT electronic controller (plug-in cases, standard)[82] | Lamp green offMechanical controller: the DEFROST button has been pressed, cooling is off and manual defrost is on; press again to restart cooling. Defrost symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| AHT electronic controller (plug-in cases, standard)[82] | Display -d- / dFr.Defrost in progress (AHT controller). (The manual does not give the colour.) Defrost symbol: red steady |
| AHT electronic controller (plug-in cases, standard)[82] | Display dEFDefrost in progress (SECOP controller or automatic defrost). (The manual does not give the colour.) Defrost symbol: red steady |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | LED defrostDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | Display -d-Defrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Heatcraft Beacon II[30] | Display dEFDefrost in progress. Defrost symbol: red steady |
| Heatcraft Beacon II[30] | Display drnDrain (drip) time after defrost. Defrost symbol: red steady |
| Danfoss ETC (True cabinets)[142] | Icon defrost heaterThe defrost heater is on. (The manual does not give the colour.) Defrost symbol: red steady |
| Danfoss ETC (True cabinets)[142] | Display dEFA defrost is in progress (e.g. after a manual defrost). (The manual does not give the colour.) Defrost symbol: red steady |
| Danfoss EKC 202A/B/C[2] | LED defrost steadyDefrost relay is on, defrost in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Danfoss EKC 202A/B/C[2] | Display -d-Defrost is running or the room is still pulling down after defrost (shown up to 15 min). (The manual does not give the colour.) Defrost symbol: red steady |
| Carel Heos[18] | Defrost button backlight onA manually started defrost is running. (The manual does not give the colour.) Defrost symbol: white steady |
| LAE AT1-5/AT2-5[166] | Display DEFDefrost in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| LAE AR2/BR1/BIT25 and BR+/CD25/TM (True cabinets)[146] | Icon defrostThe defrost heater is on / the appliance is defrosting. (The manual does not give the colour.) Defrost symbol: red steady |
| LAE AR2/BR1/BIT25 and BR+/CD25/TM (True cabinets)[146] | Display dEFDefrost in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Full Gauge MT-514E Faston[122] | LED defrostDefrost is on. (The manual does not give the colour.) Defrost symbol: red steady |
| Full Gauge MT-514E Faston[122] | Display dEFr On / OFFManual defrost started or ended from the keypad. (The manual does not give the colour.) Defrost symbol: red steady |
| Full Gauge MT-514E Faston[122] | Display drAiProcess stage: drainage after defrost. (The manual does not give the colour.) Defrost symbol: red steady |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | LED defrost onDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | LED defrost flashingDrip time after defrost (d7): compressor and fans stay off. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM ML Controller case controller[134] | LED defrostDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| RDM ML Controller case controller[134] | Display dEFControl state: defrost. (The manual does not give the colour.) Defrost symbol: red steady |
| Taylor C392/C393/C394 frozen beverage freezers[150] | Icon defrost valveThe barrel defrost valve is open. (The manual does not give the colour.) Defrost symbol: white steady |
| Full Gauge TC-900E Log[118] | LED defrostThe defrost output is on. (The manual does not give the colour.) Defrost symbol: red steady |
| Full Gauge TC-900E Log[118] | Display Pre,Process stage: pre-defrost. (The manual does not give the colour.) Defrost symbol: red steady |
| Full Gauge TC-900E Log[118] | Display dEFrProcess stage: defrost. (The manual does not give the colour.) Defrost symbol: red steady |
| Full Gauge TC-900E Log[118] | Display dRAiProcess stage: drainage (drip time). (The manual does not give the colour.) Defrost symbol: red steady |
| Dixell XM669K/XM679K[50] | Icon defrost onDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Dixell XR70CX[54] | LED defrost onDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Dixell XR70CX[54] | LED defrost flashingDrip time after defrost is running. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-CC 550A[3] | Icon defrost steadyDefrost relay is on. (The manual does not give the colour.) Defrost symbol: red steady |
| Danfoss AK-CC 550A[3] | Display -d-Defrost sequence in progress, including drip-down, fan delay and pull-down. (The manual does not give the colour.) Defrost symbol: red steady |
| Carel ir33[11] | Icon defrost steadyDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Danfoss AK-CC55 Water Loop[35] | Display icon defrost steadyDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Danfoss AK-CC55 Water Loop[35] | Display -d-Defrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Danfoss Optyma control AK-RC 113[39] | Icon fan flashingFans are paused after defrost (parameter F4). (The manual does not give the colour.) Fan symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss Optyma control AK-RC 113[39] | Icon defrost steadyDefrost is called for. (The manual does not give the colour.) Defrost symbol: red steady |
| Danfoss Optyma control AK-RC 113[39] | Icon defrost flashingDrip time after defrost is running (parameter d7). (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-RC 251[47] | Icon fan flashingFans should run but are held by a delay (drip time). (The manual does not give the colour.) Fan symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-RC 251[47] | Icon defrost steadyDefrost relay is on. (The manual does not give the colour.) Defrost symbol: red steady |
| Dixell XR06CX[51] | LED defrost steadyDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Dixell XR06CX[51] | LED defrost flashingDrip time is in progress. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XR06CX[51] | LED fan flashingFan delay after defrost is running. (The manual does not give the colour.) Fan symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XW60K/XW60L[55] | LED defrost steadyDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Dixell XW60K/XW60L[55] | LED defrost flashingDrip time is in progress. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | Symbol defrostDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | Display dEFAutomatic defrost is in progress (max. 60 min). (The manual does not give the colour.) Defrost symbol: red steady |
| Full Gauge TC-940R[119] | LED DEFR steadyDefrost (heating) output is on. (The manual does not give the colour.) Defrost symbol: red steady |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | Remote pre-heat indicatorDefrost cycle has started. (The manual does not give the colour.) Defrost symbol: white steady |
| Temperzone UC6 unit controller[135] | DS1 digit 8De-ice mode or the time-out after de-ice. (The manual does not give the colour.) Defrost symbol: red steady |
| Dixell XR03CX/XR04CX (Hillphoenix display cases)[159] | LED defrost steadyDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Dixell XR03CX/XR04CX (Hillphoenix display cases)[159] | LED defrost flashingDrip time is in progress. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Pego 202BASE electronic board[167] | LED defrost flashingDrip time after defrost (d7) is running. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Vaillant aroSTOR plus VWL B/BM 200/6, 260/6[171] | Symbol de-icingManual de-icing is running (ends after 8 min). (The manual does not give the colour.) Defrost symbol: white steady |
| Dixell XR60CX[12] | LED defrost steadyDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Dixell XR60CX[12] | LED defrost flashingDrip (dripping) time after defrost is running. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33+ VCC[20] | Defrost icon steadyDefrost is in progress (dEF). (The manual does not give the colour.) Defrost symbol: red steady |
| Carel SmartCella / SmartCella 3PH[24] | Defrost icon steadyDefrost is active. (The manual does not give the colour.) Defrost symbol: red steady |
| Carel SmartCella / SmartCella 3PH[24] | LED DEFROST yellow steady (3PH panel)Power is available at the defrost terminals. Defrost symbol: yellow steady |
| Danfoss AK-CC 450[32] | LED defrost steadyDefrost relay is on; defrost in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Danfoss AK-CC 750[36] | Display LED 3 (defrost) steadyDefrost relay on (EKA display front LED). (The manual does not give the colour.) Defrost symbol: red steady |
| Dixell XR35CX[52] | LED defrost steadyDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Dixell XR35CX[52] | LED defrost flashingDrip time after defrost is running. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XWi70K[56] | LED defrost steadyDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Dixell XWi70K[56] | LED defrost flashingDrip time after defrost is running. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel µChiller[60] | Defrost icon steadyDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Carel µChiller[60] | Defrost icon flashingDripping time after defrost. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| AHT GD-Cooler (GD-XLS, GD-XL)[84] | LED symbol defrost steadyAutomatic or manual defrost is running. (The manual does not give the colour.) Defrost symbol: red steady |
| RDM Mercury 3 Twin Coil[92] | LED defrost steadyDefrost cycle in progress (pump-down and heating stages; off again during drain-down and fan delay). (The manual does not give the colour.) Defrost symbol: red steady |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | DEFROST/STAND BY lamp orange steadyHeating is being prepared: defrost or warm-up standby before the fan starts. Defrost symbol: orange steady |
| Full Gauge MT-512E 2HP[120] | LED defrost steadyDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | LED defrost steadyDefrost cycle in progress (pump-down and heating stages; off during drain-down and fan delay). (The manual does not give the colour.) Defrost symbol: red steady |
| Carel PQ (True cabinets)[144] | Defrost icon steadyDefrost heaters are energised. (The manual does not give the colour.) Defrost symbol: red steady |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | Defrost LED steadyDefrost is active. (The manual does not give the colour.) Defrost symbol: red steady |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | Defrost LED flashingDefrost started manually or by digital input. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel MPXzero (Hillphoenix display cases)[160] | Defrost icon steadyDefrost is active. (The manual does not give the colour.) Defrost symbol: red steady |
| alpha innotec BWP 190S/260S DHW heat pump[168] | Symbol defrost shownEvaporator defrost is in progress. (The manual does not give the colour.) Defrost symbol: white steady |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red long pulsesHeat pump defrost is running. Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | dFDefrost operation is running. Normal. |
| Fujitsu AIRSTAGE J-II VRF – indoor units (Operation/Timer/Filter lamps)[199] | Operation 6 s on / 2 s offDefrost or oil recovery is running in the outdoor unit. Normal; the indoor fan may stop or slow down meanwhile. (The manual does not give the colour.) Defrost symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| LAE BR1-27/BR1-28/BR5-A/BR5-B/BD1-28/CD25[165] | Icon defrost output steadyThe defrost output is energised. (The manual does not give the colour.) Defrost symbol: red steady |
| Thermia Atella / Robust[114] | Symbol defrostDefrosting is active. (The manual does not give the colour.) Defrost symbol: yellow steady |
| Carel MasterCella[7] | Defrost icon steadyDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Carel μC2SE[8] | LED defrost steadyDefrost is in progress. Defrost symbol: orange steady |
| Carel μC2SE[8] | LED defrost flashingDefrost has been requested and is waiting to start. Defrost symbol: orange ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Pego 202BASE electronic board[167] | LED defrost steadyDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Dixell XW270L/XW271L[9] | LED defrost onA defrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Dixell XW270L/XW271L[9] | LED defrost flashingDrip time after defrost is running. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XW270L/XW271L[9] | DEFROST button LED onA manual defrost has been started. (The manual does not give the colour.) Defrost symbol: red steady |
| Eliwell ID 974[13] | LED defrost onA defrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Eliwell ID 974[13] | LED defrost flashingDefrost has been called manually or by a digital input. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Evco EV3203[107] | LED defrost steadyDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Evco EV3203[107] | LED defrost blinkingDefrost is delayed or the evaporator is dripping after defrost. (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Evco EVK214[109] | LED defrost steadyDefrost is in progress. (The manual does not give the colour.) Defrost symbol: red steady |
| Evco EVK214[109] | LED defrost blinkingDefrost is waiting for compressor protection, the evaporator is dripping (d7), or the refrigerant is being heated (dA). (The manual does not give the colour.) Defrost symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
The lamp or symbol shows that a defrost or the drip time after it is running.
Check: Nothing to do; if the defrost never ends, troubleshoot the defrost.
Alarm lamp: an alarm is active
| Controller | Code |
|---|---|
| Danfoss ERC 21X[1] | Icon alarm steadyAn alarm is active; read the A/E code shown alternately with the temperature. (The manual does not give the colour.) Alarm symbol: red steady |
| Copeland EazyCool ZX (XCM25D)[5] | LED alarm flashingA new alarm has occurred; open the alarm menu to read it. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland EazyCool ZX (XCM25D)[5] | LED alarm (active) onAn alarm is currently active. (The manual does not give the colour.) Alarm symbol: red steady |
| Carel EVD ice / EVD mini[17] | Red LED flashingAn alarm is active; read the A/E code on the display. Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel MPXone[21] | Alarm icon (triangle) flashingAn alarm is active; the code is shown on the display. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel MPXone[21] | ALARM button LED flashingAn active alarm is present. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel MPXone[21] | ALARM button LED onAlarm has been acknowledged (buzzer muted). (The manual does not give the colour.) Alarm symbol: red steady |
| Carel µRack[25] | Icon ALARM onAn alarm is active; the display alternates value and alarm code. (The manual does not give the colour.) Alarm symbol: red steady |
| Carel µRack[25] | Red ALARM LED onA manual-reset alarm (compressor/fan overload) is or was active today; outputs stay disabled until alarms are cleared with A19. Alarm symbol: red steady |
| Carel µRack[25] | Icon suction probe + ALARM flashingSuction probe alarm: high or low value, or probe not connected. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel µRack[25] | Icon discharge probe + ALARM flashingDischarge probe alarm: high value or probe not connected. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland Large ZX 22–30 HP[29] | LED ! on (upper)A new alarm has occurred; open the alarm menu. (The manual does not give the colour.) Alarm symbol: red steady |
| Copeland Large ZX 22–30 HP[29] | LED ! on (lower)An alarm is currently active. (The manual does not give the colour.) Alarm symbol: red steady |
| Danfoss AK-CC 550 / 550B[33] | All LEDs flashingAn alarm is active; press the top button briefly to show the code and acknowledge. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-PC 781A[37] | LED Alarm flashingActive or unacknowledged alarm. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-PC 781A[37] | LED Alarm steadyActive alarm that has been acknowledged. (The manual does not give the colour.) Alarm symbol: red steady |
| Danfoss EKC 202D1[41] | LEDs flashing fastAn alarm is active; push the top button to show the alarm code. (The manual does not give the colour.) Alarm symbol: red flashing fast |
| Dixell XEV12D[49] | LED superheat alarm onSuperheat is outside its alarm limits. Alarm symbol: red steady |
| Dixell XR460C[53] | Icon alarm onAn alarm is active; read the code on the display. (The manual does not give the colour.) Alarm symbol: red steady |
| Pego ECP200 EXPERT PULSE[89] | Icon alarm flashingAn alarm is present; its code alternates with the temperature. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Pego ECP200 EXPERT PULSE[89] | Icon alarm steadyAn alarm occurred and has since cleared; press UP to reset the memory. (The manual does not give the colour.) Alarm symbol: red steady |
| Secop SLV controller 105N46xx[81] | LED Alarm onAn alarm is active; short press the upper button to see the code. (The manual does not give the colour.) Alarm symbol: red steady |
| Secop SLV controller 105N46xx[81] | External alarm LED (DI1 = 17) onMirrors the display Alarm LED: an alarm is active. (The manual does not give the colour.) Alarm symbol: red steady |
| Störk-Tronic ST121 / ST501 / ST551[93] | Display flashingAn alarm is active (with A15 = 1, 3 or 5); read the alarm code. Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland compressor electronics communications (20–40 ton scroll)[65] | LED red flash + solid red (lockout)Compressor is locked out; the red flash code before it shows the cause. Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM Mercury / Intuitive Mercury thermostats and monitors[129] | LED alarm (red) onA fault or alarm is detected; read it on the display. Alarm symbol: red steady |
| RDM Intuitive Bitzer IQ Rack (BITZER CM-RC-01 alarms)[133] | Status bar redAn alarm condition is present. Alarm symbol: red steady |
| Danfoss ERC 11x (True and Beverage-Air cabinets)[141] | Icon alarm onAn alarm is active; read the code on the display. (The manual does not give the colour.) Alarm symbol: red steady |
| Dixell XR/XW (True cabinets)[145] | Icon alarm onAn alarm is active; read the code on the display. (The manual does not give the colour.) Alarm symbol: red steady |
| Taylor frozen beverage freezers C300, C302, C303/C314, 345/346/349/355[149] | LCD FAULT flashingA machine fault has occurred (with warning tone); read the fault message. (The manual does not give the colour.) Alarm symbol: white ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel iJF with VCC (Hillphoenix SMD-H)[161] | Icon service onAn alarm is active (service/maintenance indication); read the code on the display. (The manual does not give the colour.) Service symbol: red steady |
| Toshiba Digital Inverter / Super Digital Inverter RAV (RAV-SM, RAV-RM, RAV-GM, RAV-HM light commercial split)[125] | Receiver lamps Operation/Timer/Ready flashingWireless models: an error is shown by the lamp pattern; read the check code with the remote or the service table. (The manual does not give the colour.) Alarm symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| AHT electronic controller (plug-in cases, standard)[82] | Display flashing pointElectronic controller: an alarm is active; press STANDBY briefly to show the fault code. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| AHT electronic controller (plug-in cases, standard)[82] | Display red point next to hornSECOP controller: an alarm is active and stays lit until the fault is fixed; press STANDBY RESET to see the code. Alarm symbol: red steady |
| Danfoss AK-CC55 (Single Coil, Multi Coil, Compact)[34] | LED alarmAn alarm is active; hold the alarm button 3 s to read the code. (The manual does not give the colour.) Alarm symbol: red steady |
| Danfoss AK-PC 782A/782B[38] | LED Alarm flashingAn alarm is active or not yet acknowledged. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| BAC TrilliumSeries adiabatic cooler TRF[174] | EC fan LED orangeEC fan motor: a warning is active. Fan symbol: orange steady |
| BAC TrilliumSeries adiabatic cooler TRF[174] | EC fan LED redEC fan motor: failure; the motor status relay opens. Fan symbol: red steady |
| BAC TrilliumSeries adiabatic cooler TRF[174] | HMI fan dot redFan status Alarm: a fan alarm is active; see the fan alarms menu. Fan symbol: red steady |
| BAC TrilliumSeries adiabatic cooler TRF[174] | HMI alarm row redThe alarm in that row is active; inactive alarms are not highlighted. Alarm symbol: red steady |
| Copeland PerformanceAlert diagnostic module[62] | LED yellow long flash + codeOne long yellow flash before the flash code means the module has locked the compressor out; count the following flashes for the cause. Alarm symbol: yellow ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss EKC 202A/B/C[2] | LEDs flashingAn alarm is active; press the top button briefly to read the code and acknowledge it. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss EKC 326A[42] | All four LEDs flashingA regulation error is active; push the upper button briefly to show the code and cancel the alarm. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland EXD-SH1/2[26] | LED alarm onAn alarm is active; read the code on the display. (The manual does not give the colour.) Alarm symbol: red steady |
| Danfoss VLT HVAC Basic Drive FC 101[70] | LED Warn. yellowA warning is active; read the code on the display. The motor may keep running. Alarm symbol: yellow steady |
| Danfoss VLT HVAC Basic Drive FC 101[70] | LED Alarm red flashingThe drive has tripped on an alarm; fix the cause, then press Reset (a trip lock needs a mains power cycle). Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss VLT HVAC Basic Drive FC 101[70] | LED Warn. + Alarm flashingDirectly after a trip both warning and alarm flash; when the cause is gone only the alarm keeps flashing until reset. Alarm symbol: yellow ● → red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Danfoss VLT FC 103[14] | LED Warn yellow steadyA warning is active; the display shows the warning text and number. Alarm symbol: yellow steady |
| Danfoss VLT FC 103[14] | LED Alarm red flashingAn alarm has tripped the drive; read the alarm number and reset after the cause is fixed. Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss VLT FC 103[14] | LED Warn yellow + Alarm red flashingTrip lock: the drive is locked out; cycle the mains power after fixing the cause. Alarm symbol: yellow ● → red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Carel Heos[18] | Alarm LED red flashingA new alarm is active (buzzer and alarm relay on if configured); press Alarm to read it. Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel Heos[18] | Power+ LED RUN/FAULT redThe Power+ drive has an alarm; read the drive alarm on the controller. Alarm symbol: red steady |
| HTPG EcoNet enabled unit coolers[162] | Red LED above display flashingAn alarm is active; read it under Service > Current Alarms. Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Hussmann parallel rack / CO2 cascade (basic alarm package)[86] | Alarm indicator lightBasic alarm package: the lit indicator shows which alarm (oil failure, phase loss, low liquid, high suction, high discharge or compressor failure) has tripped; with an electronic rack controller read the alarm there. (The manual does not give the colour.) Alarm symbol: red steady |
| LAE AT1-5/AT2-5[166] | Indicator alarmAn alarm is active; read the code on the display. (The manual does not give the colour.) Alarm symbol: red steady |
| LAE AR2/BR1/BIT25 and BR+/CD25/TM (True cabinets)[146] | Icon alarmAR2/BR1/BIT25: an alarm is active; read the code (hi, Lo, do, E1-E3). (The manual does not give the colour.) Alarm symbol: red steady |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | Group icon yellow ×MJ-310E: equipment in the group is abnormal; open the group to read the error code. Alarm symbol: yellow steady |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | Mark at top right of group iconMJ-310E: abnormality in the outdoor unit, sub outdoor unit, BC controller, gateway or interface unit of that group. (The manual does not give the colour.) Alarm symbol: white steady |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | Message bar Serious failureMJ-310E: abnormality in an interface unit (IFU) or gateway (G/W). (The manual does not give the colour.) Alarm symbol: white steady |
| Mitsubishi Electric City Multi (M-NET error codes)[102] | Message bar Slight failureMJ-310E: abnormality in an air conditioning unit. (The manual does not give the colour.) Alarm symbol: white steady |
| Full Gauge MT-514E Faston[122] | LED alarmAn alarm is active; read the message on the display. (The manual does not give the colour.) Alarm symbol: red steady |
| NIBE F1255 ground source heat pump[78] | Front lamp redA-alarm: an alarm icon shows in the display and the heat pump may reduce comfort or stop; read the alarm number. Alarm symbol: red steady |
| NIBE F1255 ground source heat pump[78] | Front lamp green + service symbolB-alarm (information alarm): a temporary fault the heat pump handles itself; it resets automatically and is not logged. Service symbol: green steady |
| NIBE F1255 ground source heat pump[78] | Inverter status LED red steadyThe inverter has an alarm; read the alarm in the heat pump display. Alarm symbol: red steady |
| Danfoss Optyma iCO2[46] | Icon alarm/warning redAn alarm or warning is active; read the A, E or H code on the MMILDS display. Alarm symbol: red steady |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | LED alarm onAn alarm or warning is active, or an EH/EL temperature alarm has cleared but not yet been acknowledged (press mute). (The manual does not give the colour.) Alarm symbol: red steady |
| Pego ECP202 EXPERT / ECP202 EXPERT D7.5[90] | LED alarm flashing + temperature flashingRoom temperature is outside the A1/A2 limits; the buzzer sounds. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel pRack pR300[22] | Terminal LED red flashingOne or more alarms are active and not yet acknowledged; press Alarm to read them. Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel pRack pR300[22] | Icon alarm (main screen)An alarm is active, manual operation is on, or a prevent function (e.g. high-pressure prevent) is acting; open the alarm list. (The manual does not give the colour.) Alarm symbol: white steady |
| RDM Mercury AC and roof top unit controllers[130] | LED alarmAn alarm is active; read the message on the display. (The manual does not give the colour.) Alarm symbol: red steady |
| RDM ML Controller case controller[134] | LED alarmAn alarm is active; read the message on the display. (The manual does not give the colour.) Alarm symbol: red steady |
| Taylor C392/C393/C394 frozen beverage freezers[150] | Yellow triangle on touchscreenA machine fault has occurred (warning tone sounds); open the fault screen to read it. Alarm symbol: yellow steady |
| Taylor C392/C393/C394 frozen beverage freezers[150] | Red rectangle in Current ConditionsThe input or barrel shown in red has an active fault. Alarm symbol: red steady |
| Taylor C392/C393/C394 frozen beverage freezers[150] | PNR LED red fast flashingA fault has occurred on that barrel (flashes at about half-second intervals). Alarm symbol: red flashing fast |
| Taylor R280 fry dispenser[158] | Display and basket LEDs flashing with ErrAn error has been detected on that side; read the Err number and press Enter to reset. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | OPERATION green + TIMER orange flashing 5 HzProtection for the connecting cable / serial signal or another protection (including compressor); read the check code with the remote controller. Alarm symbol: green + orange flashing fast |
| Toshiba RAS residential split and multi-split (RAS-2M…5M G3, RAS-B J2, RAS-PKVPG; check codes)[126] | All indoor lamps flashing 5 Hz + beeps (service mode)During remote-controller self-diagnosis: the check code now shown is the fault. Alarm symbol: green + orange flashing fast |
| Vaillant uniTOWER plus VIH QW 190/6 E / aroTHERM plus split[170] | Symbol fault F.XXXA fault is active; the F code (with plain text) replaces the basic display. (The manual does not give the colour.) Alarm symbol: white steady |
| Dixell XM669K/XM679K[50] | Icon generic alarmAn alarm is active; read the code on the display. (The manual does not give the colour.) Alarm symbol: red steady |
| Dixell XR70CX[54] | LED alarm onAn alarm is active; read the code on the display. (The manual does not give the colour.) Alarm symbol: red steady |
| Danfoss AK-CC 550A[3] | All icons flashingAn alarm is active; press the top button to read the code. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33[11] | Icon alarm flashingAn alarm is active (e.g. high/low temperature or external input); read the code. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33[11] | Icon service (spanner) flashingInternal malfunction such as an EEPROM error or a probe fault; call service. (The manual does not give the colour.) Service symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33[11] | Icon HACCP flashingNew HACCP alarms (HA and/or HF) are stored and not yet cleared. (The manual does not give the colour.) HACCP symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33 universale[19] | Icon alarm flashingAn alarm is active, including immediate or delayed external input alarms; read the code. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33 universale[19] | Icon service (spanner) flashingMalfunction such as an EEPROM error or probe fault; also shown for the signal-only alarm E17. (The manual does not give the colour.) Service symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel pRack pR300T (transcritical CO2)[23] | Terminal LED red flashingActive alarm that has not been acknowledged; press Alarm to read it. Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel pRack pR300T (transcritical CO2)[23] | Terminal LED red steadyAlarm present and acknowledged, or an auto-reset alarm still waiting to be viewed. Alarm symbol: red steady |
| Copeland Stream condensing units (Next Gen CoreSense)[27] | LED green flashingWarning condition; the compressor keeps running. Count the flashes for the cause. Alarm symbol: green ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland Stream condensing units (Next Gen CoreSense)[27] | LED orange flashingTrip; the compressor has stopped and restarts by itself after a set time. Count the flashes. Alarm symbol: orange ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland Stream condensing units (Next Gen CoreSense)[27] | LED red flashingLockout; manual reset is needed. Count the flashes for the cause. Alarm symbol: red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Sanhua SEC60x[31] | LED alarm steadyAn alarm is active; read the code on the display. (The manual does not give the colour.) Alarm symbol: red steady |
| Danfoss AK-CC55 Water Loop[35] | Display alarm LED steadyAn alarm is active; hold the alarm button for 3 s to read the code. (The manual does not give the colour.) Alarm symbol: red steady |
| Danfoss Optyma control AK-RC 113[39] | Icon alarm steadyAn alarm occurred and has cleared; it is shown until acknowledged. (The manual does not give the colour.) Alarm symbol: red steady |
| Danfoss Optyma control AK-RC 113[39] | Icon alarm flashingAn alarm is in progress; read the code on the display. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss EKE 1A/1B/1C/1D[43] | Status LED red flickeringAlarm or error condition; read the code. Alarm symbol: red flashing fast |
| Danfoss AK-RC 251[47] | Icon alarm steadyAn alarm is active (not a HACCP alarm); read the code. (The manual does not give the colour.) Alarm symbol: red steady |
| Dixell XW60K/XW60L[55] | LED alarm steadyAn alarm is active; read the code. (The manual does not give the colour.) Alarm symbol: red steady |
| Carel µC2SE for process chiller[59] | Icon alarm red steadyAn alarm is active; read the code. Alarm symbol: red steady |
| Copeland CoreSense Communications (13–15 ton scroll)[67] | LED yellow 2Compressor ran 12 s to 15 min and then tripped for more than 7 min; repeated events lead to lockout (red 2). Alarm symbol: yellow ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Copeland CoreSense Communications (13–15 ton scroll)[67] | LED red N + solid redLockout: the red flash code is followed by a pause and a steady red phase; power cycle or Modbus reset is needed. Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| AHT electronic controller (Nidec/Secop, e.g. Kinley XL)[83] | Symbol alarmAn alarm is active; the error code alternates with the temperature. Stays until the fault is cleared. (The manual does not give the colour.) Alarm symbol: red steady |
| RDM DMTouch / miniDM[91] | LED alarm flashingAn alarm directed to the front panel is active (sounder also on). (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Kriwan INT69 PYF Diagnose[95] | LED red 6 / orange 3Cos phi monitoring: value outside the permitted limit. Alarm symbol: red ●●●●●● → orange ●●● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 PYF Diagnose[95] | LED green / orange flashingWarning pending; count green then orange pulses (same table as the red codes). Alarm symbol: green ● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Kriwan INT69 PYF Diagnose[95] | LED red / orange flashingFault, motor shut down; count red then orange pulses. Alarm symbol: red ● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Full Gauge TC-940R[119] | LED ALRM steadyAlarm output is on; read the message. (The manual does not give the colour.) Alarm symbol: red steady |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | Remote operation lamp flashingA fault or protective device has stopped the unit; read the check code. (The manual does not give the colour.) Alarm symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Toshiba VRF high-temperature hot water module MMW-AP0481CHQ-E (R134a)[127] | Remote check code / service displayA protective device has operated or a fault occurred; read the check code. (The manual does not give the colour.) Alarm symbol: white steady |
| RDM Intuitive / Mercury pack and condenser controllers[131] | LED alarm steadyAn alarm is active; read the message on the display. (The manual does not give the colour.) Alarm symbol: red steady |
| Temperzone UC6 unit controller[135] | Alarm LED (AOUT 4) flashingExternal 7-segment alarm LED flashes with the alarm code. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| True Ice TI/TCIM ice machines[147] | UV LED red slow flashingUV lamp current too low. Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| True Ice TI/TCIM ice machines[147] | UV LED red fast flashingUV lamp overload (current too high). Alarm symbol: red flashing fast |
| True Ice TI/TCIM ice machines[147] | Alert triangle on home screenAn alarm is active; press the triangle to read it. (The manual does not give the colour.) Alarm symbol: yellow steady |
| Copeland (CPC) E2 RX/BX/CX controller[163] | Case controller alarm LEDs red flashing 2/sCC-100/CS-100 is in fail-safe mode (corrupt set point or software, or failed sensors). Alarm symbol: red flashing fast |
| Pego 202BASE electronic board[167] | LED alarm flashingTemperature alarm (below A1 or above A2); the temperature also flashes and the buzzer sounds. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carpigiani AES PSP[15] | CHECK LED flashingAn alarm has occurred; press STOP to show the last alarm. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carpigiani AES PSP[15] | CHECK LED steadyReminder of an earlier alarm, or a pasteurisation that was repeated after a blackout. (The manual does not give the colour.) Alarm symbol: red steady |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | Remote operation LED flashingUnit stopped by a malfunction; the code is shown on the wired remote. (The manual does not give the colour.) Alarm symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Daikin RA / SkyAir / VRV (malfunction codes)[75] | Indoor unit operation LED flashingUnit stopped by a malfunction (wireless remote); read the code via inspection mode. (The manual does not give the colour.) Alarm symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss Optyma Plus[4] | All LEDs flashingAn alarm is active and the alarm relay has cut in; press the top button to read the code. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel μC2SE[8] | LED alarm steadyAn alarm is active; read the code on the display. Alarm symbol: red steady |
| Dixell XR60CX[12] | LED alarm steadyAn alarm is active; read the code on the display. (The manual does not give the colour.) Alarm symbol: red steady |
| Carel EVD evolution / EVD evolution twin[16] | LED alarm red steadyA system alarm is active (probe, EEPROM, valve motor; also mains failure when an Ultracap/battery module closes the valve); control alarms do not light it. Alarm symbol: red steady |
| Carel ir33+ VCC[20] | Alarm icon flashingAn alarm is active; the code (E0, LO, HI, UCF, COM …) is shown on the display. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel SmartCella / SmartCella 3PH[24] | Alarm icon flashingAn alarm is active (e.g. high/low temperature or a malfunction); read the code. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel SmartCella / SmartCella 3PH[24] | Service (spanner) icon flashingMalfunction such as EEPROM error or faulty probe; read the code. (The manual does not give the colour.) Service symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel SmartCella / SmartCella 3PH[24] | HACCP icon flashingA HACCP alarm has been stored; check HA/HF. (The manual does not give the colour.) HACCP symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel SmartCella / SmartCella 3PH[24] | LED ALARM red steady (3PH panel)Alarm: breaker QF1, motor protector QM1 or alarm input (HP switch/compressor protector) has tripped. Alarm symbol: red steady |
| Danfoss AK-CC 450[32] | All LEDs flashingAn alarm is active and the alarm relay has cut in; push the top button to read and accept the code. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-CC 750[36] | LED Alarm flashingActive alarm not yet acknowledged. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss AK-CC 750[36] | LED Alarm steadyActive alarm that has been acknowledged. (The manual does not give the colour.) Alarm symbol: red steady |
| Danfoss AK-CC 750[36] | Display LEDs flashingAn alarm has been triggered; press the top button to show the code. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss EKE 100[44] | LED alarm red flashing 1 HzAn alarm or warning is active on valve A or B; read the code. Alarm symbol: red ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Dixell XC645D[48] | LED load 1–4 flashing 2 HzDigital-input safety alarm for that load, or the load is disabled for maintenance; read the display. (The manual does not give the colour.) Compressor symbol: red flashing fast |
| Dixell XC645D[48] | LED alarm steadyAn alarm is active; read the code. (The manual does not give the colour.) Alarm symbol: red steady |
| Dixell XC645D[48] | LED alarm-log flashingA new alarm has occurred; open the alarm log. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Dixell XR35CX[52] | LED alarm steadyAn alarm is active; read the code on the display. (The manual does not give the colour.) Alarm symbol: red steady |
| Dixell XWi70K[56] | LED alarm steadyAn alarm is active; read the code (in Pr2 it marks parameters also present in Pr1). (The manual does not give the colour.) Alarm symbol: red steady |
| Carel µChiller[60] | Service (spanner) icon flashingSerious alarm that needs a qualified technician; read the code. (The manual does not give the colour.) Service symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Danfoss GD gas detection (Basic/Premium/Heavy Duty units, controller unit)[72] | LED yellow steadyA fault is pending (see System Errors / error memory). Alarm symbol: yellow steady |
| Danfoss DHP heat pumps (DHP-A/AL/C/H/L)[76] | Alarm indicator flashingAn alarm has blocked the heat pump (e.g. HP/LP switch, overheat protector); read the text and reset by switching the operating mode to OFF and back. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| AHT GD-Cooler (GD-XLS, GD-XL)[84] | Display code flashing alternating with temperatureA fault is active (P1, P2, HA, LA, noL); it stays until the fault is cleared. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM Mercury 3 Twin Coil[92] | LED alarm steadyAn alarm is active; read the message on the display. (The manual does not give the colour.) Alarm symbol: red steady |
| Kriwan INT69 UY Diagnose[96] | LED green / orange (warning)Warning: machine in a critical range but still running; count green then orange pulses, same numbering as the red error codes. Alarm symbol: green ● → orange ● · 0.35 s on, 0.35 s off · 0.8 s between colours · pause 1.5 s |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | ON/OFF lamp green blinking (wired remote)Remote controller is starting up, or the unit has stopped on an error; read the check code. Alarm symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp green blinking (indoor unit)Unit stopped on a malfunction; run the self-check to read the code. Alarm symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Mitsubishi Electric Mr. Slim PLA-RP indoor units (check codes)[104] | Operation lamp B 14 flashesOther outdoor error; see the outdoor unit service manual (pattern B = outdoor/other unit: lamp on for about 3 s, then the flashes). Alarm symbol: green ●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2.5 s (timing assumed, not stated in the manual) |
| Copeland Electronic Unit Controller[116] | LED alarm-menu flashingA new alarm has been recorded. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Copeland Electronic Unit Controller[116] | LED alarm steadyAn alarm is active; read the code on the display. (The manual does not give the colour.) Alarm symbol: red steady |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | Light block Timer + Ready alternate blinkingIndoor fan, drain overflow or liquid backflow fault (P01, P10, P12, P13); read the 7-segment code. (Operation off.) (The manual does not give the colour.) Alarm symbol: yellow ● → orange ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | Light block Operation + Ready alternate blinkingOutdoor protective stop (P03–P31: discharge temp., HP switch, phase/voltage, heat sink, gas leak, 4-way valve, fan IPDU …); read the 7-segment code. (Timer off.) (The manual does not give the colour.) Alarm symbol: green ● → orange ● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Toshiba VRF SMMS / SHRM / Mini-SMMS (MMY, MCY, MMU, MML, MMD, MMF, MMC indoor units; check codes)[124] | Indoor P.C. board LED flashing (CHK pin test)During the CHK-pin test the float switch or fan motor is abnormal (LED is lit when normal). (The manual does not give the colour.) Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM Mercury / Intuitive Mercury case and coldroom controllers[128] | LED alarm steadyAn alarm is active (e.g. MOP); read the message on the display. (The manual does not give the colour.) Alarm symbol: red steady |
| RDM Intuitive Superpack / Transcritical Superpack[132] | Status bar red flashingNew alarm active; sounder on. Press accept to mute. Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| RDM Intuitive Superpack / Transcritical Superpack[132] | Status bar red steadyAlarm still active but accepted (sounder muted); bar returns to blue when the alarm clears. Alarm muted symbol: red steady |
| Eliwell controller (Beverage-Air DW deep well refrigerators)[148] | Alarm LED steadyAn alarm is active; read the code. (The manual does not give the colour.) Alarm symbol: red steady |
| Taylor R160 frozen food dispenser[156] | Alarm LED steadyAn alarm is active; read the code (HA, LA, P1). (The manual does not give the colour.) Alarm symbol: red steady |
| Carel MPXzero (Hillphoenix display cases)[160] | Alarm icon red flashingAn alarm is active; the code is shown on the display. Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel MPXzero (Hillphoenix display cases)[160] | Alarm icon red steadyAlarm acknowledged (still present until the cause clears). Alarm muted symbol: red steady |
| BAC Nexus modular hybrid cooler (NXF controls)[172] | Alarm button redAn alarm is present; press the button to show the alarm description. Alarm symbol: red steady |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | EE:EEAn error is stored: switch the unit off and hold the two buttons given for the model (e.g. Energy Save + Zone Control, or both temperature buttons) for about 3–5 s to show the code and unit address. |
| Fujitsu non-inverter outdoor unit PCB (older, two red LEDs)[189] | LED 1 6 + LED 2 steadyThe indoor unit reports a fault; read the code at the indoor unit. red ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Staff BTX/BFX automatic batch freezers (BTX150, BFX150, BFX200, BFX201, BFX400, BFX600, BFX1000, BFX1500)[193] | Long repeated beepsMachine alarm (agitator motor thermal protection, inverter alarm or memory alarm); read the error shown on the display. |
| Fujitsu AIRSTAGE J-II VRF – wired and simple remote controllers UTY-RNK*, UTY-RSK*, UTY-RHK* (error code on the display)[197] | 9UOutdoor unit error: the fault is in the outdoor unit. Read the code on the outdoor 7-segment display (E.xx.x) or with the group RC. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.5U.1Indoor unit error: an indoor unit has a fault; press SELECT/ENTER to see which address. Check that indoor unit’s code (indoor troubleshooting 1–11). |
| Fujitsu AIRSTAGE J-II VRF – network convertor UTY-VGGX (group remote or single split connection)[202] | 5UIndoor or outdoor unit error on the unit connected to the convertor. Read and clear the fault on that indoor or outdoor unit. |
| Fujitsu AIRSTAGE J-II VRF – indoor units (Operation/Timer/Filter lamps)[199] | Operation 9 + Timer 15 + Filter flashing fastOutdoor unit error (code 9U): read the outdoor 7-segment display. Some outdoor faults are not shown on the indoor unit. The Filter lamp flickers fast (0.1 s) as the error marker; Operation and Timer flash their counts in turn. (The manual does not give the colour.) green + orange + red ●●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | LED102 ERROR flashing fastAn error is active (LED102 flashes about 0.1 s on/off while LED101 stays lit); the display shows Err. and the code, step through several codes with SELECT. red flashing fast |
| LAE BR1-27/BR1-28/BR5-A/BR5-B/BD1-28/CD25[165] | Icon alarm steadyAn alarm is active; any key mutes the buzzer. (The manual does not give the colour.) Alarm symbol: red steady |
| Thermia Atella / Robust[114] | Alarm indicator green flashingAn alarm is active; the alarm text is shown in the display. Alarm symbol: green ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel MasterCella[7] | Alarm icon flashingAn alarm is active, e.g. high/low temperature or an external digital-input alarm. (The manual does not give the colour.) Alarm symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel MasterCella[7] | Service icon (spanner) flashingInternal fault such as an EEPROM error or a probe fault; call service. (The manual does not give the colour.) Service symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel MasterCella[7] | HACCP icon flashingNew HACCP alarms (HA and/or HF) are stored. (The manual does not give the colour.) HACCP symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel pRack pR300T (transcritical CO2)[23] | Main screen alarm signal (field 4)The main screen shows a signal that an alarm is active. (The manual does not give the colour.) Alarm symbol: white steady |
| RDM Intuitive Superpack / Transcritical Superpack[132] | Remote display fault LED1 (pressure) onRemote display LED1 signals a pressure fault. (The manual does not give the colour.) Alarm symbol: red steady |
| RDM Intuitive Superpack / Transcritical Superpack[132] | Remote display fault LED2 (status input) onRemote display LED2 signals a status-input fault. (The manual does not give the colour.) Alarm symbol: red steady |
| Carel ir33+ VCC[20] | Service (spanner) icon flashing with alarm iconShown together with the flashing alarm icon for probe faults, pump-down, low pressure, condenser, door, EEPROM and VCC faults. (The manual does not give the colour.) Service symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Carel ir33+ VCC[20] | HACCP icon flashing (HA/HF)A HACCP alarm (HA or HF) has been recorded. (The manual does not give the colour.) HACCP symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Störk-Tronic ST121 / ST501 / ST551[93] | ST551 LED1 on (default)With factory settings LED1 on the ST551 shows an alarm. (The manual does not give the colour.) Alarm symbol: red steady |
| Pego 202BASE electronic board[167] | LED alarm steadyAn EL or EH temperature alarm has cleared but stays shown until acknowledged with the mute key. (The manual does not give the colour.) Alarm symbol: red steady |
| Dixell XW270L/XW271L[9] | LED alarm onAn alarm is active; in the Pr2 menu it instead marks a parameter that is also in Pr1. (The manual does not give the colour.) Alarm symbol: red steady |
| Eliwell ID 974[13] | LED alarm onAn alarm is active (buzzer sounds if fitted). (The manual does not give the colour.) Alarm symbol: red steady |
| Evco EV3 300 series[108] | LED alarm steadyAn alarm is active; read the code on the display. (The manual does not give the colour.) Alarm symbol: red steady |
| Evco EVK214[109] | LED HACCP blinkingAt least one new HACCP alarm has been stored; view it in the LS list. (The manual does not give the colour.) HACCP symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| Evco EVK214[109] | LED alarm steadyAn alarm or error is active; read the code on the display. (The manual does not give the colour.) Alarm symbol: red steady |
The lamp or symbol only shows that an alarm is active; the code in the display or the alarm list tells which.
Check: Read the code in the display or the alarm log and look it up on this page.
Thermal disinfection (legionella) not completed
| Controller | Code |
|---|---|
| IVT AirX air-to-water heat pump[175] | 5284The hot water peak did not reach 65 °C within its three-hour window; a new attempt is made the following night. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5284Thermal disinfection failed: continuous hot water draw or heater output too low for the tank volume; retried the next day. |
| IVT Geo 500/600 series ground source heat pump[177] | 5284Thermal disinfection (legionella peak) failed: heater overheat protector tripped, continuous hot water draw or heater output too low; retried the next day. |
| IVT Geo 312/412 ground source heat pump[178] | 5284Thermal disinfection failed: heater overheat protector tripped, hot water drawn continuously, or heater output set too low for the tank volume. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5284Thermal disinfection failed: continuous hot water draw or heater output too low for the tank volume; retried the next day. |
The hot water tank did not reach the disinfection temperature within the time allowed, so the anti-legionella cycle was not completed; most units try again at the next scheduled time.
Check: Check whether hot water was drawn during the cycle, that the immersion heater works and its overheat protector has not tripped, that its output is high enough for the tank volume and that the tank sensor sits correctly. Repeated failures leave the tank without legionella protection.
Brine temperature out of range
| Controller | Code |
|---|---|
| IVT Geo 500/600 series ground source heat pump[177] | 5547Incoming brine TB0 below about -6 °C (borehole) or 2 °C (groundwater) (warning). |
| IVT Geo 500/600 series ground source heat pump[177] | 5549Incoming brine TB0 below about -6 °C (borehole) or 2 °C (groundwater) (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5551Brine sensor TB1 below about -6 °C (borehole) or 2 °C (groundwater) (warning). |
| IVT Geo 500/600 series ground source heat pump[177] | 5553Brine sensor TB1 below about -6 °C (borehole) or 2 °C (groundwater) (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5555Incoming brine TB0 too warm (warning). |
| IVT Geo 500/600 series ground source heat pump[177] | 5557Incoming brine TB0 too warm (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5559Brine sensor TB1 too warm (warning). |
| IVT Geo 500/600 series ground source heat pump[177] | 5561Brine sensor TB1 too warm (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5585The low pressure transmitter indicates a problem on the brine side (too cold brine or too little brine flow). |
| IVT Geo 312/412 ground source heat pump[178] | 5547Incoming brine TB0 below about -6 °C (borehole) or 2 °C (groundwater) (warning). |
| IVT Geo 312/412 ground source heat pump[178] | 5549Incoming brine TB0 below about -6 °C (borehole) or 2 °C (groundwater) (alarm). |
| IVT Geo 312/412 ground source heat pump[178] | 5551Brine sensor TB1 below about -6 °C (borehole) or 2 °C (groundwater) (warning). |
| IVT Geo 312/412 ground source heat pump[178] | 5553Brine sensor TB1 below about -6 °C (borehole) or 2 °C (groundwater) (alarm). |
| IVT Geo 312/412 ground source heat pump[178] | 5555Incoming brine TB0 too warm (warning). |
| IVT Geo 312/412 ground source heat pump[178] | 5557Incoming brine TB0 too warm (alarm). |
| IVT Geo 312/412 ground source heat pump[178] | 5559Brine sensor TB1 too warm (warning). |
| IVT Geo 312/412 ground source heat pump[178] | 5561Brine sensor TB1 too warm (alarm). |
| IVT Geo 312/412 ground source heat pump[178] | 5585The low pressure transmitter indicates a problem on the brine side (too cold brine or too little brine flow). |
The brine (collector fluid) entering or leaving a ground or water source heat pump is colder or warmer than the limits for the collector type, so the unit warns and then stops the compressor.
Check: Compare the brine in and out temperatures with the limits, check the brine flow (pump, strainer, air), the antifreeze concentration and whether the borehole or ground loop is undersized or overloaded by long running at high output. Too warm brine can point to a wrong sensor or an external heat source in the loop.
Water or brine temperature sensor fault
| Controller | Code |
|---|---|
| IVT AirX air-to-water heat pump[175] | 5204Supply (flow) temperature sensor T0: open circuit. |
| IVT AirX air-to-water heat pump[175] | 5205Supply (flow) temperature sensor T0: short circuit. |
| IVT AirX air-to-water heat pump[175] | 5206Supply temperature sensor T0 alarm after three faults within 3 h or a fault lasting 30 min. |
| IVT AirX air-to-water heat pump[175] | 5207Heating-medium outlet sensor TC1 (water leaving the heat pump): open circuit. |
| IVT AirX air-to-water heat pump[175] | 5208Heating-medium outlet sensor TC1 (water leaving the heat pump): short circuit. |
| IVT AirX air-to-water heat pump[175] | 5209Heating-medium outlet sensor TC1 (water leaving the heat pump): faulty (alarm stage). |
| IVT AirX air-to-water heat pump[175] | 5213Heating-medium return sensor TC0 (water entering the heat pump): open circuit. |
| IVT AirX air-to-water heat pump[175] | 5214Heating-medium return sensor TC0 (water entering the heat pump): short circuit. |
| IVT AirX air-to-water heat pump[175] | 5215Heating-medium return sensor TC0 (water entering the heat pump): faulty (alarm stage). |
| IVT AirX air-to-water heat pump[175] | 5234Pool temperature sensor TP1: open circuit. |
| IVT AirX air-to-water heat pump[175] | 5235Pool temperature sensor TP1: short circuit. |
| IVT AirX air-to-water heat pump[175] | 5236Pool temperature sensor TP1: faulty (alarm stage). |
| IVT AirX air-to-water heat pump[175] | 5237Hot water sensor TW1: open circuit. |
| IVT AirX air-to-water heat pump[175] | 5238Hot water sensor TW1: short circuit. |
| IVT AirX air-to-water heat pump[175] | 5239Hot water sensor TW1: faulty (alarm stage). |
| IVT AirX air-to-water heat pump[175] | 5320Condenser outlet sensor TC3 (heating water leaving the condenser): open circuit. |
| IVT AirX air-to-water heat pump[175] | 5321Condenser outlet sensor TC3 (heating water leaving the condenser): short circuit. |
| IVT AirX air-to-water heat pump[175] | 5322Condenser outlet sensor TC3 (heating water leaving the condenser): faulty (alarm stage). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5204Supply (flow) temperature sensor T0: open circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5205Supply (flow) temperature sensor T0: short circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5206Supply temperature sensor T0 alarm after three faults within 3 h or a fault lasting 30 min. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5207Heating-medium outlet sensor TC1 (water leaving the heat pump): open circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5208Heating-medium outlet sensor TC1 (water leaving the heat pump): short circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5209Heating-medium outlet sensor TC1 (water leaving the heat pump): faulty (alarm stage). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5213Heating-medium return sensor TC0 (water entering the heat pump): open circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5214Heating-medium return sensor TC0 (water entering the heat pump): short circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5215Heating-medium return sensor TC0 (water entering the heat pump): faulty (alarm stage). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5234Pool temperature sensor TP1: open circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5235Pool temperature sensor TP1: short circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5236Pool temperature sensor TP1: faulty (alarm stage). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5237Hot water sensor TW1: open circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5238Hot water sensor TW1: short circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5239Hot water sensor TW1: faulty (alarm stage). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5320Condenser outlet sensor TC3 (heating water leaving the condenser): open circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5321Condenser outlet sensor TC3 (heating water leaving the condenser): short circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5322Condenser outlet sensor TC3 (heating water leaving the condenser): faulty (alarm stage). |
| IVT Geo 500/600 series ground source heat pump[177] | 5204Supply (flow) temperature sensor T0: open circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5205Supply (flow) temperature sensor T0: short circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5206Supply (flow) temperature sensor T0: faulty (alarm stage). |
| IVT Geo 500/600 series ground source heat pump[177] | 5207Heating-medium outlet sensor TC1 (water leaving the heat pump): open circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5208Heating-medium outlet sensor TC1 (water leaving the heat pump): short circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5209Heating-medium outlet sensor TC1 (water leaving the heat pump): faulty (alarm stage). |
| IVT Geo 500/600 series ground source heat pump[177] | 5213Heating-medium return sensor TC0 (water entering the heat pump): open circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5214Heating-medium return sensor TC0 (water entering the heat pump): short circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5215Heating-medium return sensor TC0 (water entering the heat pump): faulty (alarm stage). |
| IVT Geo 500/600 series ground source heat pump[177] | 5234Pool temperature sensor (TP1, called TC1 in the description): open circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5235Pool temperature sensor: short circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5236Pool temperature sensor alarm after three faults within 3 h or 15 min with an open or short circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5237Hot water sensor TW1: open circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5238Hot water sensor TW1: short circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5239Hot water sensor TW1: faulty (alarm stage). |
| IVT Geo 500/600 series ground source heat pump[177] | 5320Condenser sensor TC3 (heating water leaving the condenser): open circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5321Condenser sensor TC3 (heating water leaving the condenser): short circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5322Condenser sensor TC3 (heating water leaving the condenser): faulty (alarm stage). |
| IVT Geo 500/600 series ground source heat pump[177] | 5545Both brine sensors TB0 (in) and TB1 (out) are open or short-circuited. |
| IVT Geo 500/600 series ground source heat pump[177] | 5571Brine in sensor TB0: short circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5573Brine in sensor TB0: open circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5575Brine in sensor TB0 faulty (alarm stage). |
| IVT Geo 500/600 series ground source heat pump[177] | 5577Brine out sensor TB1: short circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5579Brine out sensor TB1: open circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5581Brine out sensor TB1 faulty (alarm stage). |
| IVT Geo 500/600 series ground source heat pump[177] | 6216Upper hot water sensor TW2 signal outside the allowed range (info). |
| IVT Geo 500/600 series ground source heat pump[177] | 6217No signal from upper hot water sensor TW2 (info). |
| IVT Geo 500/600 series ground source heat pump[177] | 6218Upper hot water sensor TW2 signal outside the allowed range (alarm). |
| IVT Geo 312/412 ground source heat pump[178] | 5204Supply (flow) temperature sensor T0: open circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5205Supply (flow) temperature sensor T0: short circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5206Supply (flow) temperature sensor T0: faulty (alarm stage). |
| IVT Geo 312/412 ground source heat pump[178] | 5207Heating-medium outlet sensor TC1 (water leaving the heat pump): open circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5208Heating-medium outlet sensor TC1 (water leaving the heat pump): short circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5209Heating-medium outlet sensor TC1 (water leaving the heat pump): faulty (alarm stage). |
| IVT Geo 312/412 ground source heat pump[178] | 5213Heating-medium return sensor TC0 (water entering the heat pump): open circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5214Heating-medium return sensor TC0 (water entering the heat pump): short circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5215Heating-medium return sensor TC0 (water entering the heat pump): faulty (alarm stage). |
| IVT Geo 312/412 ground source heat pump[178] | 5234Pool temperature sensor (TP1, called TC1 in the description): open circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5235Pool temperature sensor: short circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5236Pool temperature sensor alarm after three faults within 3 h or 15 min with an open or short circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5237Hot water sensor TW1: open circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5238Hot water sensor TW1: short circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5239Hot water sensor TW1: faulty (alarm stage). |
| IVT Geo 312/412 ground source heat pump[178] | 5320Condenser sensor TC3 (heating water leaving the condenser): open circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5321Condenser sensor TC3 (heating water leaving the condenser): short circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5322Condenser sensor TC3 (heating water leaving the condenser): faulty (alarm stage). |
| IVT Geo 312/412 ground source heat pump[178] | 5545Both brine sensors TB0 (in) and TB1 (out) are open or short-circuited. |
| IVT Geo 312/412 ground source heat pump[178] | 5571Brine in sensor TB0: short circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5573Brine in sensor TB0: open circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5575Brine in sensor TB0 faulty (alarm stage). |
| IVT Geo 312/412 ground source heat pump[178] | 5577Brine out sensor TB1: short circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5579Brine out sensor TB1: open circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5581Brine out sensor TB1 faulty (alarm stage). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5204Supply (flow) temperature sensor T0: open circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5205Supply (flow) temperature sensor T0: short circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5206Supply temperature sensor T0 alarm after three faults within 3 h or a fault lasting 30 min. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5207Heating-medium outlet sensor TC1 (water leaving the heat pump): open circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5208Heating-medium outlet sensor TC1 (water leaving the heat pump): short circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5209Heating-medium outlet sensor TC1 (water leaving the heat pump): faulty (alarm stage). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5213Heating-medium return sensor TC0 (water entering the heat pump): open circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5214Heating-medium return sensor TC0 (water entering the heat pump): short circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5215Heating-medium return sensor TC0 (water entering the heat pump): faulty (alarm stage). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5234Pool temperature sensor TP1: open circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5235Pool temperature sensor TP1: short circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5236Pool temperature sensor TP1: faulty (alarm stage). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5237Hot water sensor TW1: open circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5238Hot water sensor TW1: short circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5239Hot water sensor TW1: faulty (alarm stage). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5320Condenser outlet sensor TC3 (heating water leaving the condenser): open circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5321Condenser outlet sensor TC3 (heating water leaving the condenser): short circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5322Condenser outlet sensor TC3 (heating water leaving the condenser): faulty (alarm stage). |
A temperature sensor on the water side (supply, return, heating medium, hot water, pool or brine) reads open circuit, short circuit or an implausible value, so the unit runs on a fallback value or stops the function that uses it.
Check: Measure the sensor resistance against the manufacturer's table at a known temperature, check the cable and terminals for breaks, damage and moisture, and check that the sensor sits properly in its pocket or on the pipe.
Refrigerant circuit temperature sensor fault
| Controller | Code |
|---|---|
| IVT AirX air-to-water heat pump[175] | 5314Discharge (hot gas) sensor TR6: open circuit. |
| IVT AirX air-to-water heat pump[175] | 5315Discharge (hot gas) sensor TR6: short circuit. |
| IVT AirX air-to-water heat pump[175] | 5316Discharge (hot gas) sensor TR6: faulty (alarm stage). |
| IVT AirX air-to-water heat pump[175] | 5414Liquid line sensor TR3 (heating mode): open circuit. |
| IVT AirX air-to-water heat pump[175] | 5415Liquid line sensor TR3 (heating mode): short circuit. |
| IVT AirX air-to-water heat pump[175] | 5416Liquid line sensor TR3 (heating mode): faulty (alarm stage). |
| IVT AirX air-to-water heat pump[175] | 5420Liquid line sensor TR4 (cooling mode): open circuit. |
| IVT AirX air-to-water heat pump[175] | 5421Liquid line sensor TR4 (cooling mode): short circuit. |
| IVT AirX air-to-water heat pump[175] | 5422Liquid line sensor TR4 (cooling mode): faulty (alarm stage). |
| IVT AirX air-to-water heat pump[175] | 5531Compressor temperature sensor TR1: open circuit. |
| IVT AirX air-to-water heat pump[175] | 5532Compressor temperature sensor TR1: short circuit. |
| IVT AirX air-to-water heat pump[175] | 5533Compressor temperature sensor TR1: faulty (alarm stage). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5314Discharge (hot gas) sensor TR6: open circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5315Discharge (hot gas) sensor TR6: short circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5316Discharge (hot gas) sensor TR6: faulty (alarm stage). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5414Liquid line sensor TR3 (heating mode): open circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5415Liquid line sensor TR3 (heating mode): short circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5416Liquid line sensor TR3 (heating mode): faulty (alarm stage). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5420Liquid line sensor TR4 (cooling mode): open circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5421Liquid line sensor TR4 (cooling mode): short circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5422Liquid line sensor TR4 (cooling mode): faulty (alarm stage). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5531Compressor temperature sensor TR1: open circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5532Compressor temperature sensor TR1: short circuit. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5533Compressor temperature sensor TR1: faulty (alarm stage). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5622Discharge (hot gas) sensor TR6 fault, LG code 41 (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5623Discharge (hot gas) sensor TR6 fault, LG code 41 (alarm). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5626Evaporator (probably mid-coil) temperature sensor TR8 fault, LG code 45 (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5627Evaporator (probably mid-coil) temperature sensor TR8 fault, LG code 45 (alarm). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5650Condenser outlet temperature sensor TR7: open circuit (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5651Condenser outlet temperature sensor TR7: short circuit (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5652Condenser outlet temperature sensor TR7 faulty (alarm). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5656Condenser inlet temperature sensor TR3: open circuit (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5657Condenser inlet temperature sensor TR3: short circuit (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5658Condenser inlet temperature sensor TR3 faulty (alarm). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5664Evaporator inlet temperature sensor TR4 open or short-circuited, LG code 48 (info). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5665Evaporator inlet temperature sensor TR4 faulty, LG code 48. |
| IVT Geo 500/600 series ground source heat pump[177] | 5314Discharge (hot gas) sensor TR6: open circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5315Discharge (hot gas) sensor TR6: short circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5316Discharge (hot gas) sensor TR6: faulty (alarm stage). |
| IVT Geo 500/600 series ground source heat pump[177] | 5414Liquid line sensor TR3 (heating mode): open circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5415Liquid line sensor TR3 (heating mode): short circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5416Liquid line sensor TR3 (heating mode): faulty (alarm stage). |
| IVT Geo 500/600 series ground source heat pump[177] | 5420Liquid line sensor TR4 (cooling mode): open circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5421Liquid line sensor TR4 (cooling mode): short circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5422Liquid line sensor TR4 (cooling mode): faulty (alarm stage). |
| IVT Geo 500/600 series ground source heat pump[177] | 5531Compressor temperature sensor TR1: open circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5532Compressor temperature sensor TR1: short circuit. |
| IVT Geo 500/600 series ground source heat pump[177] | 5533Compressor temperature sensor TR1: faulty (alarm stage). |
| IVT Geo 312/412 ground source heat pump[178] | 5314Discharge (hot gas) sensor TR6: open circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5315Discharge (hot gas) sensor TR6: short circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5316Discharge (hot gas) sensor TR6: faulty (alarm stage). |
| IVT Geo 312/412 ground source heat pump[178] | 5414Liquid line sensor TR3 (heating mode): open circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5415Liquid line sensor TR3 (heating mode): short circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5416Liquid line sensor TR3 (heating mode): faulty (alarm stage). |
| IVT Geo 312/412 ground source heat pump[178] | 5420Liquid line sensor TR4 (cooling mode): open circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5421Liquid line sensor TR4 (cooling mode): short circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5422Liquid line sensor TR4 (cooling mode): faulty (alarm stage). |
| IVT Geo 312/412 ground source heat pump[178] | 5531Compressor temperature sensor TR1: open circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5532Compressor temperature sensor TR1: short circuit. |
| IVT Geo 312/412 ground source heat pump[178] | 5533Compressor temperature sensor TR1: faulty (alarm stage). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5314Discharge (hot gas) sensor TR6: open circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5315Discharge (hot gas) sensor TR6: short circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5316Discharge (hot gas) sensor TR6: faulty (alarm stage). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5414Liquid line sensor TR3 (heating mode): open circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5415Liquid line sensor TR3 (heating mode): short circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5416Liquid line sensor TR3 (heating mode): faulty (alarm stage). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5420Liquid line sensor TR4 (cooling mode): open circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5421Liquid line sensor TR4 (cooling mode): short circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5422Liquid line sensor TR4 (cooling mode): faulty (alarm stage). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5531Compressor temperature sensor TR1: open circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5532Compressor temperature sensor TR1: short circuit. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5533Compressor temperature sensor TR1: faulty (alarm stage). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5597Evaporator temperature sensor TR4: short circuit (warning). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5598Evaporator temperature sensor TR4: open circuit (warning). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5599Evaporator temperature sensor TR4 faulty (alarm). |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 2 + Timer 3Indoor coil (pipe) thermistor open or short circuit (code 04/05): measure the thermistor; replace the PCB only if the sensor is good. red + green ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 2 + Timer 4Indoor heat exchanger (middle) thermistor fault on models that have a second coil sensor. red + green ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 3 + Timer 2Discharge pipe thermistor open or short circuit (code 0C/0d). red + green ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 3 + Timer 3Outdoor heat exchanger thermistor open or short circuit (code 06/07). red + green ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter wall-mounted split (indoor Operation/Timer lamps)[180] | Operation 3 + Timer 8Compressor body thermistor open or short circuit (code 15). red + green ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 2 + Timer 3Indoor heat exchanger thermistor open or short circuit (04/05). green + orange ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 3 + Timer 2Discharge pipe thermistor fault (0C/0d). green + orange ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 3 + Timer 3Outdoor heat exchanger thermistor fault (06/07). green + orange ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 3 + Air Clean 2Thermistor at the 2-way (liquid) valve of this indoor unit's circuit is faulty (1d). green + blue ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 3 + Air Clean 3Thermistor at the 3-way (gas) valve of this indoor unit's circuit is faulty (1E). green + blue ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone indoor units ASU/ARU/AUU …RML (Operation/Timer/Air Clean/Coil Dry lamps)[181] | Operation 3 + Timer 8Compressor thermistor fault (15). green + orange ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 2 flashesOutdoor discharge pipe thermistor fault. red ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 3 flashesOutdoor heat exchanger thermistor fault. red ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 5 flashes2-way (liquid) valve thermistor for indoor unit A is faulty. red ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 2 5 flashes2-way (liquid) valve thermistor for indoor unit B is faulty. red ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 3 5 flashes2-way (liquid) valve thermistor for indoor unit C is faulty. red ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 6 flashes3-way (gas) valve thermistor for indoor unit A is faulty. red ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 2 6 flashes3-way (gas) valve thermistor for indoor unit B is faulty. red ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 3 6 flashes3-way (gas) valve thermistor for indoor unit C is faulty. red ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 4 6 flashes3-way (gas) valve thermistor for indoor unit D is faulty. red ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 7 flashesCompressor thermistor fault. red ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu multi-zone outdoor unit AOU24RML/AOU36RML (PCB LED 1–4)[182] | LED 1 16 flashesOutdoor heat exchanger middle thermistor fault. red ●●●●●●●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 04Indoor coil (pipe) thermistor open circuit. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 05Indoor coil (pipe) thermistor short circuit. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 06Outdoor coil (pipe) thermistor open circuit. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 07Outdoor coil (pipe) thermistor short circuit. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 0CDischarge pipe thermistor open circuit. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 0dDischarge pipe thermistor short circuit. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 15Compressor temperature thermistor fault. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 1d2-way (liquid) valve thermistor fault (multi units). |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 1E3-way (gas) valve thermistor fault on multi units; the older UK guide lists an expansion valve error. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 28Indoor heat exchanger temperature abnormal. |
| Fujitsu wired remote controller (error code + unit address after EE:EE)[183] | 29Outdoor heat exchanger middle temperature abnormal. |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | E4:00Indoor coil thermistor open circuit or missing. |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | E5:00Indoor coil thermistor short circuit. |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | E6:00Outdoor coil thermistor open circuit or missing. |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | E7:00Outdoor coil thermistor short circuit. |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | EC:00Discharge pipe thermistor open circuit. |
| Fujitsu wired remote controller, older models (E-codes with unit address)[184] | ED:00Discharge pipe thermistor short circuit. |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation blinking + Timer 3Outdoor pipe thermistor fault. green + red ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation blinking + Timer 5Discharge thermistor open circuit. green + red ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation blinking + Timer 5 + Swing blinkingDischarge thermistor short circuit. green + red + yellow ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation blinking + Timer 9Compressor temperature thermistor fault. green + red ●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation 3 + Timer blinkingIndoor pipe thermistor open circuit. green + red ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu cassette, ceiling and duct units AUY/ABY/AWY with wireless remote (older, UK)[185] | Operation 3 + Timer blinking + Swing blinkingIndoor pipe thermistor short circuit. green + red + yellow ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wall-mounted multi indoor units (older, UK; two-stage lamp code)[186] | Red 2 + Green blinking, test button: Red blinking + Green 3Indoor sensor fault group; after the test button: indoor pipe thermistor. red + green ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wall-mounted multi indoor units (older, UK; two-stage lamp code)[186] | Red blinking + Green 2, test button: Red 2 + Green blinkingOutdoor thermistor group; after the test button: discharge thermistor. red + green ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wall-mounted multi indoor units (older, UK; two-stage lamp code)[186] | Red blinking + Green 2, test button: Red 4 + Green blinkingOutdoor thermistor group; after the test button: outdoor pipe thermistor. red + green ●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wall-mounted multi indoor units (older, UK; two-stage lamp code)[186] | Red blinking + Green 2, test button: Red 8 + Green blinkingOutdoor thermistor group; after the test button: compressor temperature thermistor. red + green ●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wall-mounted multi indoor units (older, UK; two-stage lamp code)[186] | Red blinking + Green 2, test button: Red 9 + Green blinkingOutdoor thermistor group; after the test button: 2-way valve thermistor. red + green ●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu wall-mounted multi indoor units (older, UK; two-stage lamp code)[186] | Red blinking + Green 2, test button: Red 10 + Green blinkingOutdoor thermistor group; after the test button: 3-way valve thermistor. red + green ●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 9–30 (older, one red LED)[187] | LED red 2Discharge thermistor fault. red ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 9–30 (older, one red LED)[187] | LED red 3Outdoor pipe thermistor fault. red ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 9–30 (older, one red LED)[187] | LED red 52-way valve thermistor fault. red ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 9–30 (older, one red LED)[187] | LED red 63-way valve thermistor fault. red ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 9–30 (older, one red LED)[187] | LED red 7Compressor thermistor fault. red ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 36–54 (older, one red LED)[188] | LED red 2Discharge thermistor fault. red ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 36–54 (older, one red LED)[188] | LED red 3Outdoor pipe thermistor fault. red ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter outdoor unit PCB, models 36–54 (older, one red LED)[188] | LED red 7Compressor thermistor fault. red ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu non-inverter outdoor unit PCB (older, two red LEDs)[189] | LED 1 2 + LED 2 steadyDischarge temperature thermistor fault. red ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu non-inverter outdoor unit PCB (older, two red LEDs)[189] | LED 1 3 + LED 2 steadyOutdoor pipe thermistor fault. red ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu non-inverter outdoor unit PCB (older, two red LEDs)[189] | LED 1 10 + LED 2 steadyCompressor temperature thermistor fault. red ●●●●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter multi outdoor unit AOY30 (older, LEDs A–D)[190] | LED A–D 2 flashesDischarge thermistor fault. red ●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter multi outdoor unit AOY30 (older, LEDs A–D)[190] | LED A–D 3 flashesOutdoor pipe thermistor fault. red ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter multi outdoor unit AOY30 (older, LEDs A–D)[190] | LED A–D 5 flashes2-way valve thermistor fault on this circuit. red ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter multi outdoor unit AOY30 (older, LEDs A–D)[190] | LED A–D 6 flashes3-way valve thermistor fault on this circuit. red ●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu inverter multi outdoor unit AOY30 (older, LEDs A–D)[190] | LED A–D 7 flashesCompressor thermistor fault. red ●●●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red 3 short + Green rapid (D, E, F)Indoor pipe sensor open circuit. red + green ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red 3 short + Green rapid + Yellow rapid (E, F)Indoor pipe sensor short circuit. red + green + yellow ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red long + Green 3 short (C)Pipe sensor fault. red + green ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red rapid + Green 3 short (F)Outdoor pipe sensor open circuit. red + green ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red rapid + Green 3 short + Yellow rapid (F)Outdoor pipe sensor short circuit. red + green + yellow ●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red rapid + Green 5 short (F)Discharge sensor open circuit. red + green ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu older wireless-remote indoor units ASY/ABY/AUY (UK model groups A–G, three lamps)[191] | Red rapid + Green 5 short + Yellow rapid (F)Discharge sensor short circuit. red + green + yellow ●●●●● · 0.5 s on, 0.5 s off · pause 2 s (timing assumed, not stated in the manual) |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 71Outdoor discharge thermistor TH1 open or short (E.71.1). Measure it against the thermistor A table. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 72Outdoor compressor temperature thermistor TH10 open or short (E.72.1). Measure it against the thermistor A table. |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 73Outdoor heat exchanger liquid pipe thermistor TH5 open or short (E.73.3). |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 82Sub-cool heat exchanger gas inlet (TH8) or gas outlet (TH9) thermistor fault (E.82.1/E.82.2). |
| Fujitsu AIRSTAGE J-II VRF – group remote controller UTY-CGGY/UTY-CGGG[198] | 83Liquid pipe (sub-cool heat exchanger liquid outlet, TH7) thermistor fault (E.83.2). |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.71.1Discharge thermistor TH1 short, or open after the compressor has run 5 min. Check the connector, measure TH1 off the board (thermistor A: about 49.8 kΩ at 25 °C, 6.3 kΩ at 80 °C) and 5 V DC at the PCB input. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.72.1Compressor (body) temperature thermistor TH10 short, or open after 5 min of compressor run. Measure it against the thermistor A table and check 5 V DC at the PCB input. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.73.3Outdoor heat exchanger liquid pipe thermistor TH5 open or short. Measure it (thermistor B: about 4.8 kΩ at 25 °C) and 5 V DC at the PCB input. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.82.1Sub-cool heat exchanger gas inlet thermistor TH8 open or short. Measure it (thermistor B) and 5 V DC at the PCB input. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.82.2Sub-cool heat exchanger gas outlet thermistor TH9 open or short. Measure it (thermistor B) and 5 V DC at the PCB input. |
| Fujitsu AIRSTAGE J-II VRF – outdoor unit main PCB (7-segment display, LED101/LED102)[200] | E.83.2Sub-cool heat exchanger liquid outlet thermistor TH7 open or short. Measure it (thermistor B) and 5 V DC at the PCB input. |
A temperature sensor in the refrigerant circuit (discharge, liquid line, compressor body, condenser or evaporator) reads open circuit, short circuit or an implausible value, so the protection or control that relies on it cannot work.
Check: Measure the sensor resistance against the table at a known temperature, check the cable and connector on the circuit board, and that the sensor is fixed and insulated on the right pipe.
Condensation (dew point) guard in cooling mode
| Controller | Code |
|---|---|
| IVT AirX air-to-water heat pump[175] | 5294Condensation guard tripped in cooling mode: humidity too high, or a short circuit in the sensor or its wiring (warning). |
| IVT AirX air-to-water heat pump[175] | 5295Condensation guard tripped in cooling mode: humidity too high, or a short circuit in the sensor or its wiring (alarm). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5294Condensation guard tripped in cooling mode: humidity too high, or a short circuit in the sensor or its wiring (warning). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5295Condensation guard tripped in cooling mode: humidity too high, or a short circuit in the sensor or its wiring (alarm). |
| IVT Geo 500/600 series ground source heat pump[177] | 5294The dew point guard has closed during cooling; not a fault, it clears when the humidity falls. |
| IVT Geo 500/600 series ground source heat pump[177] | 5295The dew point warning 5294 has been active for 30 min; must be reset by hand. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5294Condensation guard tripped in cooling mode: humidity too high, or a short circuit in the sensor or its wiring (warning). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5295Condensation guard tripped in cooling mode: humidity too high, or a short circuit in the sensor or its wiring (alarm). |
During cooling a humidity or condensation sensor on the supply pipe has detected that the pipes or emitters are at or below the dew point, so the unit raises the supply temperature or stops cooling to avoid condensation.
Check: Check the room humidity and the cooling supply temperature setting, that only emitters made for cooling are in the circuit and that pipes are insulated; if the guard trips in dry conditions, check the sensor and its wiring for moisture or a short circuit.
Supply temperature to the heating circuit too high
| Controller | Code |
|---|---|
| IVT AirX air-to-water heat pump[175] | 3121The temperature limiter on input MC1 of mixing module MM100 for heating circuit 1 has opened (supply too hot, e.g. for floor heating). |
| IVT AirX air-to-water heat pump[175] | 3122The temperature limiter on input MC1 of mixing module MM100 for heating circuit 2 has opened (supply too hot, e.g. for floor heating). |
| IVT AirX air-to-water heat pump[175] | 3123The temperature limiter on input MC1 of mixing module MM100 for heating circuit 3 has opened (supply too hot, e.g. for floor heating). |
| IVT AirX air-to-water heat pump[175] | 3124The temperature limiter on input MC1 of mixing module MM100 for heating circuit 4 has opened (supply too hot, e.g. for floor heating). |
| IVT AirX air-to-water heat pump[175] | 5271Supply temperature in heating circuit 1 above its alarm limit; low system pressure, air or low flow are typical causes. |
| IVT AirX air-to-water heat pump[175] | 5500The temperature limiter for floor heating on the external input has tripped; reset it and check the heating curve. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3121The temperature limiter on input MC1 of mixing module MM100 for heating circuit 1 has opened (supply too hot, e.g. for floor heating). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3122The temperature limiter on input MC1 of mixing module MM100 for heating circuit 2 has opened (supply too hot, e.g. for floor heating). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3123The temperature limiter on input MC1 of mixing module MM100 for heating circuit 3 has opened (supply too hot, e.g. for floor heating). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 3124The temperature limiter on input MC1 of mixing module MM100 for heating circuit 4 has opened (supply too hot, e.g. for floor heating). |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5271Supply temperature in heating circuit 1 above its alarm limit; low system pressure, air or low flow are typical causes. |
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5500The temperature limiter for floor heating on the external input has tripped; reset it and check the heating curve. |
| IVT Geo 500/600 series ground source heat pump[177] | 3121The temperature limiter on input MC1 of mixing module MM100 for heating circuit 1 has opened (supply too hot, e.g. for floor heating). |
| IVT Geo 500/600 series ground source heat pump[177] | 3122The temperature limiter on input MC1 of mixing module MM100 for heating circuit 2 has opened (supply too hot, e.g. for floor heating). |
| IVT Geo 500/600 series ground source heat pump[177] | 5271Supply temperature in heating circuit 1 too high: alarm limit set wrong, or low flow through the heating system. |
| IVT Geo 500/600 series ground source heat pump[177] | 5500The floor heating temperature limiter on the external input has tripped; reset it and check the heating curve. |
| IVT Geo 312/412 ground source heat pump[178] | 5271Supply temperature in heating circuit 1 too high: alarm limit set wrong, or low flow through the heating system. |
| IVT Geo 312/412 ground source heat pump[178] | 5500The floor heating temperature limiter on the external input has tripped; reset it and check the heating curve. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3121The temperature limiter on input MC1 of mixing module MM100 for heating circuit 1 has opened (supply too hot, e.g. for floor heating). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3122The temperature limiter on input MC1 of mixing module MM100 for heating circuit 2 has opened (supply too hot, e.g. for floor heating). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3123The temperature limiter on input MC1 of mixing module MM100 for heating circuit 3 has opened (supply too hot, e.g. for floor heating). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 3124The temperature limiter on input MC1 of mixing module MM100 for heating circuit 4 has opened (supply too hot, e.g. for floor heating). |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5271Supply temperature in heating circuit 1 above its alarm limit; low system pressure, air or low flow are typical causes. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5500The temperature limiter for floor heating on the external input has tripped; reset it and check the heating curve. |
The water sent out to a heating circuit is hotter than its alarm limit, or a temperature limiter (often for floor heating) on that circuit has opened, so the circuit is stopped to protect floors and pipes.
Check: Check the maximum supply temperature and heating curve settings, the mixing valve and its actuator, the flow through the circuit and the limiter setting; reset the limiter only once the cause is found.
Powered (electric) anode fault
| Controller | Code |
|---|---|
| IVT AirSplit 200/300 split air-to-water heat pump[176] | 5275The powered (electric) anode in the hot water tank is not working. |
| IVT Geo 500/600 series ground source heat pump[177] | 5275The powered (electric) anode in the hot water tank is not working. |
| IVT Geo 312/412 ground source heat pump[178] | 5275The powered (electric) anode in the hot water tank is not working. |
| IVT Vent 202/302/402 exhaust air heat pump[179] | 5275The powered (electric) anode in the hot water tank is not working. |
The impressed-current anode that protects the hot water tank against corrosion reports a fault, so the tank may not be protected.
Check: Check that the anode is connected and supplied, its cable and connections, and that the tank is filled with water; measure or replace the anode as the manufacturer describes.
Auger or gear motor speed fault
| Controller | Code |
|---|---|
| NTF linear (auger) granular ice makers, G series (G160, G280, G510/G500, G1000; GB and TB versions)[196] | Rotation sensor LED red blinkingAuger speed fault: the sensor measured below about 4 rpm or above about 13 rpm and has stopped the compressor for a new delay period. Check for ice binding in the evaporator (low water, low evaporating temperature), worn evaporator bearings and the gear motor. Symbol: red ● · 0.5 s on, 0.5 s off (timing assumed, not stated in the manual) |
| NTF linear (auger) granular ice makers, G series (G160, G280, G510/G500, G1000; GB and TB versions)[196] | Rotation sensor LED red steadyLock-out after 8 consecutive auger speed faults. Find the cause (auger, bearings, gear motor, water supply, refrigerant charge), then switch the power off and on to reset. Symbol: red steady |
The rotation sensor of an auger (flake, granular or nugget) ice maker sees the auger turning too slowly, too fast or not at all, and stops the compressor; after repeated faults it locks out. Common causes are ice binding in the evaporator, worn evaporator bearings or a failing gear motor.
Check: Check the water supply and level, the evaporating temperature and refrigerant charge (ice binding), the evaporator bearings and auger, and the gear motor and its capacitor; then reset by switching the power off and on.
The selection is our own and does not cover all codes. Source for each controller: the manual and its version.
Sources
- Danfoss – User Guide, electronic refrigeration control type ERC 21X series, BC194286421698en-001101 (2025.09); same codes in Installation Guide ERC 213 (DKRCE.PI.RL0.G5, 2016.04) and ERC 214 (AN19438642089705-000401, 2024.06)
- Danfoss – User Guide Controller for temperature control EKC 202A, B, C, RS8DZ902 (2018-10)
- Danfoss – Service guide (pocket guide) AK-CC 550A, AX278928624187en (2018)
- Danfoss – User Guide, controller for condensing unit Optyma Plus, SW 3.7x, BC172686425380en-001202 (2025.12)
- Copeland – Application guidelines, outdoor refrigeration units for A2L & A1 (ZXMY/ZXDY), AGL_Unit_ZX_A2L_A1_EN_Rev03, appendix 6; and Copeland ZX quick installation guide, TI_Unit_ZX_10_EN_Rev03
- Carel – MPX user manual, +030220191 rel. 2.0 (25/06/2001)
- Carel MasterCella – användarmanual, svensk utgåva (AB Kylmateriel), instruktion 4.0178.40 (juni 2001)
- Carel – μC2SE electronic control, user manual rel. 2.6 (08.07.2019), table of alarms
- Dixell – Installing and operating instructions XW270L–XW271L, 1592009037 r1.0 (03.08.2015)
- Daikin Europe – Technical Info ESIE 17-02, parameter and error list Zanotti GM-Uniblock & GS-Split (09/2017)
- Carel – ir33 platform user manual (ir33, ir33 power, ir33 DIN, powercompact, mastercella), +030220441 (rel. 2.5, 16.06.2010), chapter 8
- Dixell – XR60CX Digital controller with defrost and fans management, user manual 1592020060 (rel. 1.1, 27.04.2015)
- Eliwell – IDPlus 902/961/971/974 Elektroniska kontroller för kyl- och frysutrustningar, cod. 9IS54165 (rel. 07/11); Eliwell/Invensys – ID 974 user manual, cod. 9IS42066 (4/2002)
- Danfoss – VLT Refrigeration Drive FC 103 Instruction Manual 1.1–90 kW, MG16E322 (Rev. 2014-04-10, software 1.21), warnings and alarms; Operating Instructions 75–630 kW, MG16J202 (Rev. 05/2014), 9.4 table 9.1 Alarm/Warning Code List
- Carpigiani – Instruction Handbook AES PSP (AES 261/381/403/503 PSP), aes psp_EN, issue 06 (2012/04), section 5.1
- Carel – EVD evolution user manual, +0300005EN (rel. 4.2, 24.01.2024), table of alarms; EVD evolution twin user manual, +0300006EN (rel. 2.4, 30.10.2015), table of alarms
- Carel – EVD ice user manual, +0300038EN (rel. 1.2, 20.10.2020), 9.6 alarm table; EVD mini user manual, +0300036EN (rel. 1.2, 23.04.2018), 9.6 alarm table
- Carel – Heos high efficiency showcase controller user manual, +0300078EN (rel. 1.6, 23.11.2017), 8.5 alarm table
- Carel – ir33 universale electronic control user manual, +030220801 (rel. 2.3, 16.04.2012), 8.5 table of alarms
- Carel – ir33+ VCC technical supplement to the ir33+ platform manual, +040000059 (rel. 1.3, 10.09.2018), 6. alarm table (FR/DE/IT edition)
- Carel – MPXone user manual, +0300086EN (rel. 2.0, 15.10.2019), 8.4 alarm table
- Carel – pRack pR300 compressor rack controller user manual, +0300025EN (rel. 1.3, 17.12.2015), A.4 alarm table
- Carel – pRack pR300T user manual for transcritical CO2 systems, +0300018EN (rel. 1.6, 23.07.2020), 7.2 alarm table
- Carel – SmartCella/SmartCella 3PH cold room controller user manual, +0300084EN (rel. 1.2, 28.03.2017), 8.4.1 table of alarm signals
- Carel – µRack standard compressor racks single/two circuit user manual, +03P220431 (rel. 2.3, 06.06.2012), tab. 7.a
- Copeland – EXD-SH1/2 Controller with ModBus communication capability for electrical control valves, operating instructions, P/N 865917 Rev08 (18.11.2025)
- Copeland – User manual, Semi-hermetic Stream reciprocating condensing units, 2021/MEA/73 (2021)
- Copeland – User manual, ZSI scroll condensing units, 8504574 (2018, ed. 2024)
- Copeland – User manual, Large ZX 22–30HP condensing unit, 10746350 (July 2024)
- Heatcraft – Beacon II Refrigeration Systems, installation and operation manual, H-IM-79G (June 2020); and MAC Series condensing units, H-IM-67H (March 2018), Beacon II Smart Controller
- Sanhua – Electronic expansion valve controller SEC60x series, installation instructions, II-SEC60x-EN-R1709
- Danfoss – User Guide, controller for appliance control AK-CC 450, RS8EU702 (2015.10)
- Danfoss – User Guide AK-CC 550, RS8EN702 (2016-03); User guide AK-CC 550B, RS8GL402 (2018-11)
- Danfoss – User guide AK-CC55 Single Coil & Single Coil UI SW 2.4x, BC364229688105en-010401 (2026.08); User guide AK-CC55 Compact SW 2.3x, BC365212986197en-000302 (2026.08); Installation guide AK-CC55 Single Coil 084R8053, AN294432763974en-000601 (2026.04)
- Danfoss – User Guide, case controller for semi plug-in AK-CC55 Water Loop SW 1.2x, BC378540472015en-000101 (2022.04)
- Danfoss – Design Guide, controller for evaporator control AK-CC 750 (080Z0130 & 080Z0139), RS8GM222 (10-2014)
- Danfoss – User guide Capacity controller AK-PC 781A, Appendix B Alarm texts, RS8HE202 (2017-07)
- Danfoss – User Guide Pack controller AK-PC 782A, BC245386497365en-001201 (2026.09) and AK-PC 782B, BC417018981850en-000501 (2026.09), Appendix B Alarm texts
- Danfoss – User Guide Optyma control AK-RC 113 three phase, BC317523579312en-000101 (2020.03), section 7.1
- Danfoss – User Guide Superheat controller EIM 365 (PV01), BC415322248492en-000101 (2022.09), Alarms
- Danfoss – Instructions EKC 202D1 (084R8022), RI8NK459 (06-2015)
- Danfoss – Instructions EKC 326A, RI8NG552 (10/2011)
- Danfoss – User Guide Superheat controller and stepper valve driver EKE 1A, 1B, 1C, 1D, BC398828796060en-000103 (2024.08), section 8.1
- Danfoss – User Guide Superheat Controller EKE 100 (PV04), BC457625021427en-000201 (2026.06), section 6
- Danfoss – Instructions Optyma Plus OP-MPS/MPT/LPV/LPK/MPI, section 19 Module B Plus, table 1 error blink code, 118A2177D / AN37261897352602-010602 (2026.06)
- Danfoss – Application Guidelines, Optyma iCO2 condensing units R744 50 Hz, sections 9.3, 10.11 and 11, AB399636244436en-000301 (2026.03)
- Danfoss – User Guide, temperature controller for walk-in coolers and freezers type AK-RC 251, BC364433930186en-000101 (2021.02)
- Dixell – XC645D controller for compressor racks (suction and condenser), 1592001831 r3.5h (14.01.2022)
- Dixell – XEV12D on-off electronic expansion valve driver, software rel. 1.6, 1592019040 r1.6 (01.09.2025)
- Dixell – XM669K-XM679K controllers for multiplexed cabinets, rel. 5.4j, 1592023190 r5.4 (24.09.2025)
- Dixell – XR06CX digital controller with defrost and fans management, 1592020160 r1.2 (27.07.2015)
- Copeland (Dixell) – XR35CX Digital Controller I/O Manual, 026-1203 R4 (2024)
- Dixell – XR460C dual temperature controller, installing and operating instructions, 1592018110 r2.0 (06.10.2006)
- Dixell – XR70CX RTC digital controller with defrost and fans management, 1592020570 r1.0 (27.03.2015)
- Dixell – XW60K (and T620T/T620/V620/CX620), 1592026020 r2.3 (08.04.2015); Dixell – XW60L RTC digital controller for medium-low temperature refrigeration, 1592027050 r1.0 (18.03.2015)
- Dixell – XWi70K standard controller, FW rel. 21.4, 1592026640 r1.0 (04.06.2020)
- Bitzer – VARIPACK external BITZER frequency inverters FDU+6 .. FKU+260, operating instructions CB-100-2 (80060102, 06.2018), chapter 9 fault messages (Tab. 7)
- Bitzer – VARIPACK external BITZER frequency inverters, operating instructions CB-110-4 (80061604, 10.2023), STO fault code; VARIPACK IP55/66 operating instructions CB-111-3 (80061703, 11.2021)
- Carel – µC2SE for process chiller, user manual, +030220416 (rel. 2.3, 17.05.2018), chapter 8 Alarms (alarms table and 8.2)
- Carel – µChiller user manual, +0300053EN (rel. 2.1, 18.05.2021), 8.2 Alarm list
- Copeland – Copeland Digital Compressor Controller, AE8-1328 R7 (September 2024), Flash Code Troubleshooting
- Copeland (Emerson) – Copeland PerformanceAlert Diagnostic Module, AE8-1347 R3 (March 2016), Table 8 Troubleshooting
- Copeland (Emerson) – CoreSense Protection for Copeland Discus Compressors, AE8-1367 R6 (August 2018), Tables 3–6 LED flash codes
- Copeland (Emerson) – CoreSense Diagnostics for Copeland Scroll Air Conditioning Compressors, AE8-1379 R2 (February 2015), Tables 1–2
- Copeland – Compressor Electronics Communications for 20 to 40 Ton Copeland Air Conditioning Scroll Compressors, AE8-1384 R9 (July 2026), warning and alert/lockout codes, Tables 2 and 6
- Copeland – CoreSense Diagnostics for Copeland Scroll UltraTech Air Conditioning Compressors, AE8-1385 R2 (August 2024)
- Copeland – CoreSense Communications for 13 to 15 Ton Copeland Scroll Air Conditioning Compressors, AE8-1408 R3 (August 2024)
- Emerson (Copeland) – CoreSense Diagnostic Modules for Copeland Scroll Refrigeration Compressors, AE8-1424 (October 2017)
- Danfoss – Application Guide Scroll Compressors VZH088-117-170 Gen3, AB300034185311en-000501 (2021.03), Frequency converter troubleshooting; Application guidelines VLZ065 version B with CDS drive, AB444226142054en-000101 (2023.05), Troubleshooting; CDS303/803 Quick troubleshooting guide, AX404427814471en-000101 (2022.03)
- Danfoss – VLT HVAC Basic Drive FC 101 Programming Guide, AU275648914272en-000801 / 130R0221 (2024.11, software 6.4x), 5.1 table 23 Alarm/Warning Code List
- Danfoss – User Guide Danfoss Gas Sensor type DGS, BC291049702513en-000401 (2024.11), 3.9 Troubleshooting, 5.1 Error status, 5.4 Measuring values
- Danfoss – User Guide Gas Detection Units type Basic, Premium and Heavy Duty, BC272555038544en-000201 (2024.09), 4.1 Fault management; User Guide Gas Detection Controller unit and Expansion module, BC272555441546en-000201 (2022.03), 5.1.3 System messages and errors
- ebm-papst – User Manual ECCN02-CT0/ECCN06-CT0 BACnet gateway (version 1.0, 2022-01-28), table 5 fan warning and error indicator; CN1116 Modbus Display & Control Operating and Maintenance Instructions, 210-OMI14229-Iss8.1 (2021-10-05), 9 Fault indication and table 9
- ebm-papst – Operating instructions K3G310-PV69-03, item no. 57280-5-9970 (change 218409, 2020-09-10), and W3G910-LV12-36, item no. 56913-5-9970 (change 318338, 2025-05-22), 6.1 warning and status codes
- Daikin – Simple Self-Diagnosis by Malfunction Code, SM-TS3 (RA, SkyAir, VRV, PA, Heat Reclaim Ventilator; PDF 2014-10); drain codes A3/AF also Daikin AC Americas – VRV Service & Troubleshooting, Participant Guide EGVUSE09-07C (2007)
- Danfoss – Service instructions DHP-A, DHP-AL, DHP-C, DHP-H, DHP-L (incl. Opti/Opti Pro), VMGFC302 (2010), 10.1 Alarm and 10.4 Operational problems; Heat Pump Troubleshooting Guide, VMIFB202 (2024)
- LG – Multi V 5 Outdoor Units Service Manual, SM_MultiV_5_OutdoorUnits_09_18, Error Codes p. 125–216; Multi V 5 Operation & Maintenance Manual, OM_MULTI-V-5 (06/24), Error Codes
- NIBE – Service manual F1255, SEM GB 1609-1 M11932, chapter 6 Troubleshooting, Alarm list
- Heatcraft – Installation and Operations Manual A2L Unit Coolers, H-IM-UC-A2L, part no. 25012201 Rev. C (December 2025), section Refrigerant Detection System (RDS)
- Secop – Controllers for BD Compressors, Operating Instructions (BD P-Housing), DES.S.100.F2.02 (07-2016); Secop – Instructions Electronic Unit for BD35F/50F/35K/80CN, 101N0242/101N0680/682, DES.I.101.X2.02 / 520N1304 (June 2022)
- Secop – SLV Controller 105N46xx Series, Operating Instructions, DES.S.300.A2.02 (February 2013)
- AHT Cooling Systems – Betriebsanleitung / Operating manual Athen, Ibiza, Macao, Malta, Manhattan, Miami, Palma, Paris, Salzburg, Singapore, Sydney, SNr. 916026 (361929), status 09/17
- AHT Cooling Systems – Supplement Electronic controller NIDEC, Kinley XL, Snr. 377890, version 1 (12/2018); same code list in operating manual SNr. 916026 (361929), status 09/17
- AHT Cooling Systems – Betriebsanleitung / Operating instructions GD-Cooler, SNr. 352858, status 09/17
- AHT Cooling Systems – Supplementary sheet Electronic controller Danfoss, PNo. 386379 EL/0218
- Hussmann – Parallel Rack Systems Installation & Operation Manual, P/N 0427598_E (August 2018); Parallel Rack System & CO2 Cascade Installation & Operation Manual, P/N 3151784_C (October 2025)
- Hussmann – Transcritical CO2 Rack, Installation, Operation, and Service Manual, P/N 3182569_G (June 2026)
- Hussmann – Pumped Liquid CO2 Secondary Refrigeration, Installation & Operation Manual, P/N 0516803_D (June 2024)
- Pego – ECP200 EXPERT PULSE for EEV PULSE 230V, use and maintenance manual (rev. 01-24, software rel. 7), chap. 7 Diagnostics
- Pego – ECP202 EXPERT use and maintenance manual (rev. 02-25, software rel. 27), 7.1 Troubleshooting; ECP202 EXPERT D7.5 use and maintenance manual (rev. 01-21, software rel. 26), 7.1 Troubleshooting
- Resource Data Management – DMTouch & miniDM Commissioning & User Guide, PR05XX-XX (document revision 4.3.7), alarm indexes
- Resource Data Management – Mercury 3 Twin Coil Case Controller Commissioning/User Guide, PR0740/744-TWI (document revision 3.3a), display messages and network alarms
- Störk-Tronic – data sheets ST121-KD1KAR.112 (order no. 900323.001, V1.74, 04.11.2021), ST501-KC1KAR.112 (900390.001) and ST551 (900350.034), status displays and error messages
- Kriwan – INT69 F Diagnose data sheet, 710.00723.1
- Kriwan – INT69 PYF Diagnose data sheet, 710.00721.0
- Kriwan – INT69 UY Diagnose data sheet, 710.00650.1
- Kriwan – INT69 Y Diagnose data sheet, edition 710.00406.2
- Kriwan – INT69 YF Diagnose data sheet, 710.00708.1
- Mayekawa – MYPRO TOUCH Device List / MYPRO Touch Area Manual (Modbus), ALARM & FAILURE bits, Ver.208.121.135 (2014-10-23)
- Temperzone – UC8 Controller Quick Reference Operation and Fault Diagnosis (1015); Troubleshooting Guide for UC8 (v2, 0715); Service Training Manual, Issue 08 (January 2023)
- Temperzone – UC7 Controller Quick Reference Operation and Fault Diagnosis (1114); Troubleshooting Guide for UC7, revision 3 (19 October 2012)
- Mitsubishi Electric – MJ-310E Operation Manual (Management), 12 Error code list, WT03239X02
- Mitsubishi Electric – Technical & Service Manual SUZ-KA25/35/50/60/71VA4, No. OCH545 (August 2013), 11-2 trouble shooting check table
- Mitsubishi Electric – Service Manual PLA-RP35/50/60/71/100/125/140BA, No. OCH416 Revised Edition-D (September 2012), 10-2 and 10-3 self-diagnosis
- Goodman – DX20VC Condensing Unit Installation & Service Reference, IOD-4011L (9/2020), troubleshooting fault code table
- Krack – Microchannel Remote Air Cooled Condensers installation and operation manual, PN E660159_P, Tables 14–15 and 48 and section 8.3 (KB drive LED status)
- Evco – EV3203 instruction sheet, 1043203E103 (checked 2026-10-28)
- Evco – EV3 300 series instruction sheet, 1043300E103 (checked 2026-10-28)
- Evco – EVK214 instruction sheet, 104K214E05 (checked 2026-10-28)
- Evco – EV3 HP / EVD HP manual, 1443DHPE124 (checked 2026-10-28)
- Evco – EV3 CHILL / HPRU manual, 1443DCHE304 (checked 2026-10-28)
- Evco – EV3 MVC / EVD MVC manual, 1443DMVCE104 (checked 2026-10-28)
- Hitachi – Operation Manual P5417020 (2017), section 8.4 Alarm codes
- Thermia – Atella user manual 086U8113 (section 10) and Robust user manual 086U4257 (section 4)
- Thermia – Calibra user guide BWCA01UG0102 (alarm classes A, B, C; checked 2026-10-28)
- Copeland – AE8-1376 Electronic Unit Controller (2013), section 9
- Full Gauge Controls – TC-900E POWER instruction manual (Ver.04), section 7 Signals; TC-900E 2HP instruction manual (Ver.06), section 7 Signals
- Full Gauge Controls – TC-900E Log instruction manual (Ver.02), Signals
- Full Gauge Controls – TC-940R controller for refrigeration and defrost with alarm output (Version 03), 5.7 Indicators and alarms
- Full Gauge Controls – MT-512E 2HP instruction manual (Ver.13), 9 Display signalings
- Full Gauge Controls – MT-512E Log instruction manual (Ver.09), 9 Signals
- Full Gauge Controls – MT-514E Faston instruction manual (Ver.02), 7 Signals
- Castel – GoGreen Technical Handbook (R744 products), Handbook 2023, chapter 8.1 Electronic oil level regulators
- Toshiba – Service Manual SMMS-i MMY-MAP***4HT8P-E, SVM-13024-8 (2015); also Service Manual SHRM-i MMY-MAP***4FT8-E, A12-006; Service Manual Mini-SMMS MCY-MAP***HT, A05-015 (rev. Jun. 2006); Service Manuals VRF indoor units A10-033-4, A10-1420 (MMF-AP***6H-E), A10-1615 (MMU-AP***7MH-E); Installation Manuals MMU-AP***4HP-E (1114119301), MMD-AP***BHP-E (1115460102), MML-AP***4H-E (EH99879999), MML-AP***4NH-E (1112750209-1); Air-to-Air Heat Exchanger with DX-coil (and Humidifier) service and installation manuals (EH99887601-2); BACnet Interface BMS-IFBN640TLE Service Manual A10-1509
- Toshiba – Service Manual RAV-SM***4UTP-E, SVM-13010-5 (2014); also Service Manuals A08-007 (RAV-SM***4SDT-E), A10-1811 (RAV-RM***1MUT-E), A10-1906 (RAV-RM***1FT-ES), SVM-22024 (RAV-HM***01U1TP-E); Installation Manuals 1116950198-1 (RAV-SM***6BTP-E1), EB99819101 (RAV-RM***1MUT-E), EB99819301 (RAV-RM***1SDT-E), H99885801 (RAV-SM***4SDT-E), EB99832901 (RAV-RM***1FT-ES), EB99819501 (RAV-GM***1UT-E), 1114119201 (RAV 4-way cassette); remote controller RBC-AMS55E-ES installation manual
- Toshiba – Service Manual RAS-5M34G3AVG-E, SVM-23012 (2023); also SVM-22112 (RAS-2M10/2M14G3AVG-E, 2022), SVM-20012-1 (RAS-B**J2FVG-E console), SVM-18049-5 (RAS-**PKVPG-E / PAVPG-E high wall)
- Toshiba – Service Manual HT Hot Water Module MMW-AP0481CHQ-E, A10-1821 (2018); also Installation Manual EB99829001-02 (2024)
- Resource Data Management – Mercury & Intuitive Mercury Case Controller Installation & User Guide PR074X/PR075X (software 5.3M & 5.5E, 16-07-25), display messages and network alarms; also Mercury Controller PR0744 CAS (5.1M & 5.4E), Mercury 3 Controller PR0740-CAS (4.0), Mercury 2 & Intuitive Mercury Controller (rev. 2.6e), Mercury 3 Stepper PR0740-STEP (3.5), Mercury & Intuitive Mercury Stepper (V3.5/V3.0, V4.4 24 V, V3.4c mains), Intuitive Mercury LT PR0952 (1.0a), Two Section (Mercury 3 rev. 3.2b/3.3a, Mercury 2 rev. 1.0e), Two Section EEV PR07xx-TSSE (1.0a), Four Section (3.0a), Twin EEV PR07xx-2E-TWINE (3.0/3.1), Mini Intuitive 3 EEV PR068X-3EC (1.9), Mobile (Mercury 3 rev. 3.5, Mercury 2 rev. 1.2), Sub-Cooler Case (1.0b), Frequency Controller PR0740/0744-FQC (1.0g), Mercury T PR0700 (1.2a), Power Tray PR0040–45 (2.0c), Coldroom Panel PR0150 (7.7d), Stepper Coldroom Panel (7.1b), Plate Heat Exchanger PHX (3.8; Mercury 2 stepper PHX 2.4b)
- Resource Data Management – Mercury Monitor Installation & User Guide PR0744 MON (software 3.2, rev. L, 28-12-23); also Mercury 3 & Intuitive Mercury Monitor PR0740/PR0750/PR0760-MON (3.2), Mercury 2 & Intuitive Mercury Monitor (1.8b), Mercury 3 & Intuitive 5 Channel Thermostat PR0740/0750-5ISTA (3.2), Mercury 2 & Intuitive 5 Channel Thermostat (1.0d), Control Thermostat PR0740/750-STA (3.0c, 3.1d; Mercury 2 1.0b), Intuitive Mercury Thermostat & Humidistat PR0440 (3.1a)
- Resource Data Management – Mercury 3 AC Controller Commissioning/User Guide PR0740-AC (software 3.0, rev. C, 21-6-19); also Mercury 2 & Intuitive Mercury Air Conditioning (1.8a), Mercury 3 and Intuitive Mercury Roof Top Unit Controller PR07XX-RTU (3.3), Mercury 2 & Intuitive Mercury Roof Top Unit Controller (1.5b)
- Resource Data Management – Intuitive Mercury Mini Pack / Condenser Controller Installation & User Guide PR0750-MPA (rev. 3.4, 05-12-23); also Mercury 2 & Intuitive Mercury Minipack (1.6a), Intuitive Mercury Two Section Pack Controller (1.6a), Intuitive Plant Pack Controller (4.0d), Mercury 11-10PV Pack Condenser Controller PR033x (6.7c), Mercury 11-5C Condenser PR0266 (2.0a), Mercury 11-10CV PR027x (2.0a), CO2 Mini Transcritical CO2 Controller (1.6a), Mercury 6-10 Step Controller PR033x (rev. 1.6)
- Resource Data Management – Intuitive V2 & Mini Transcritical Superpack Commissioning/User Guide PR0650-STCO2 (rev. 5.9, software 6.0, 21-05-25); also Intuitive Transcritical Superpack (3.8), Intuitive V2 & Mini Superpack Controller PR0650/680-SUP (6.1a, 25-11-25), Intuitive V2 & Mini Super Pack Multi INV Controller (1.4, 16-04-25)
- Resource Data Management – Intuitive Bitzer IQ Rack Commissioning/User Guide PR0650-BITZIQ (rev. 3.1), Modbus alarms and CM-RC-01 sub alarm numbers
- Resource Data Management – ML Controller Case Controller Commissioning/User Guide PR0123 (document revision 3.4a)
- Temperzone – UC6 (Unit Controller 6) and pGD1 Service Terminal: Functionality Overview and Service Interface via the pGD
- ActronAir – Troubleshooting Guide Advance / Aires / VCC and GENESIS Units, Doc. 9590-2015-03 Ver. 12 (260219); Error Codes, 9590-0000-05
- ActronAir – Troubleshooting Guide Advance / Aires / VCC and GENESIS Units, Doc. 9590-2015-03 Ver. 12 (260219); Error Codes, 9590-0000-05
- ActronAir – Serene DS Series Troubleshooting, Doc. No. 9590-2037-03 Ver. 1 (251119); Aspire DS Troubleshooting, Doc. No. 9590-2031-03 Ver. 1; MultiElite DS Series Troubleshooting, Doc. No. 9590-2036-03 Ver. 2 (251022); Cascade DS Series Owner's Manual, Doc. No. 9590-4032 Ver. 1 (250610); R-32 Cassette 2 Owner's Manual, Doc. No. 9590-4016 Ver. 2 (220616); Universal Wired Remote Controller WC-03 Installation and Owner's Manual, Doc. No. 9590-4029 Ver. 8 (251104)
- ActronAir – Nexus Touch Controller WTC-01 Installation and Commissioning Guide, Doc. No. 9590-3039-02 Ver. 2 (251120)
- ActronAir – UltraSlim Ducted Split System Owner's Manual, Doc. No. 9590-4015 Ver. 1 (220608)
- True – Commercial Refrigeration General Control Guide, TEC_TM_001 / P#811072 (Rev. C, 2025-09-03); Beverage-Air – Installation and Operating Instructions (Danfoss ERC 112): CT 809-154A, BZ 809-236A Rev. D, WTFCS 48–96 809-256A, WTFCS 36 809-177A Rev. D, SM 809-186A, UCRF 809-175A, WTCTCS 809-260A, UCF 809-174A Rev. D, DW 809-184A
- True – Commercial Refrigeration General Control Guide, TEC_TM_001 / P#811072 (Rev. C, 2025-09-03)
- True – Commercial Refrigeration General Control Guide, TEC_TM_001 / P#811072 (Rev. C, 2025-09-03)
- True – Commercial Refrigeration General Control Guide, TEC_TM_001 / P#811072 (Rev. C, 2025-09-03)
- True – Commercial Refrigeration General Control Guide, TEC_TM_001 / P#811072 (Rev. C, 2025-09-03); True – Owner's Manual Retail Merchandiser TRM2M/TRM3M/TRM4M, 842860 Rev. H
- True – Commercial Refrigeration General Control Guide, TEC_TM_001 / P#811072 (Rev. C, 2025-09-03)
- True – Service Manual True Ice TI/TCIM, 857284 Rev. A (EN; also ES and FR editions)
- Beverage-Air – Installation and Operating Instructions, Hydrocarbon DW Deep Well Refrigerators, 809-184A
- Taylor – Operator Manuals C300 (op and opNP editions), C302, C303/C314, Models 0345/346/349/355
- Taylor – Service Manual C392, C393, C394
- Taylor – Operator Manuals C708/C716 (R449A), C708 Heat Treatment Shake Freezer (R449A), C606 Combination Freezer (R449A)
- Taylor – Operator Manuals C709/C717, C712, C713 (R449A), C612 Combination Freezer
- Taylor – Operator Manual Model 0736
- Taylor – Operator Manuals Model ISI-161TH (095616, November 2025, updated 2026-07-14) and ISI-161TI (095614)
- Taylor – Operator Manuals Icetro ISI-301TH and ISI-300TA (324027102, 2026-04-24), ISI-271THS/SHS (324022907)
- Taylor – Operator Manual R160
- Taylor – Operator Manual R200
- Taylor – Operator Manual R280
- Hillphoenix – Installation & Operations Manuals, display cases (Dixell XR03CX/XR04CX controller section): CF-R/CF-FS-R/CF-S-R (rv1-v2), BMD-R/BMD-D (rv3), OB-R, HVI-3-406R/408R (v2), HVI-4-406R/408R, HVI-4-406S (rv1), HTPT-R (rv6), CNZLA/CNEZLA R-290 (rv4), PT-R/PT-R-RRS (rv3), SMD-R (rv2), DLPF-R (rv6), PF-48/51/54/72-R (rv6), SD-H-R, SD-RG, SSA-R/SSF-R/SSAW-R (rv3), SSD-R-LT, BLF-R/BLF-D (rv3), BLF-SR/BLF-SD (rv3), QC-24/30/35-R (rv5)
- Hillphoenix – Installation & Operations Manual CF-SC (R-290), rv3 (Carel MPXzero alarm table); same controller in ONIZVA (R-290) and JNRZHSA/JNRBHSA (R-290) P119505H rev 9.0
- Hillphoenix – Installation & Operations Manual SMD-H/Deli, rv4 (Carel iJF IJFHS*/IJFHL* alarm table)
- HTPG – Troubleshooting Guide EcoNet Enabled Unit Coolers, HTPG0425_TSG (04/2025)
- CPC/HTPG – E2 Installation and Operation Manual for RX Refrigeration, BX HVAC, and CX Convenience Store Controllers, 026-1610 Rev 10 (06-APR-2010)
- Krack – Installation, Operation, and Service Manual KR-A2L Series Compact Evaporator/Unit Cooler, P/N 3227890
- LAE electronic – Instructions for use BR1-27, BR1-28, BR5-A (2022), BR5-B, BD1-28, CD25 (02-08-2024)
- LAE electronic – Instructions for use AT1-5 and AT2-5 (EN/IT)
- Pego – Scheda elettronica 202BASE guide (ITA-ENG-FRE-ESP-GER-NED, 01-24)
- alpha innotec – Betriebsanleitung Trinkwarmwasser-Wärmepumpen Innenaufstellung BWP 190S/BWP 260S, 83034800eDE (OE02:961-2105)
- alpha innotec – Betriebsanleitung Trinkwarmwasserwärmepumpe Innenaufstellung WWB 190, 83023900cDE (OE04:221-2106)
- Vaillant – uniTOWER plus VIH QW 190/6 E, Operating and installation and maintenance instructions, 0020291511_03 (16.12.2024)
- Vaillant – aroSTOR plus VWL B/BM 200/6 and 260/6 230V, Installation and maintenance instructions, 8000034704_01 (27.10.2025)
- Baltimore Aircoil – Nexus Modular Hybrid Cooler Operation & Maintenance Manual, RGOMNXF-01
- Baltimore Aircoil – Vertex Evaporative Condenser Operation & Maintenance Manual, EC fan controls (VRC-xxxxA-xxxxN-xB), RGOMVRCA01 (2025-05-29)
- Baltimore Aircoil – TrilliumSeries Adiabatic Cooler TRF Operation & Maintenance Manual, RGOMTRF303 R5.0 (2024-08-06)
- IVT – Larmkoder, ivt.se/support/larmkoder (all models listed on the page), checked 2026-11-03
- IVT – Larmkoder, ivt.se/support/larmkoder (all models listed on the page), checked 2026-11-03
- IVT – Larmkoder, ivt.se/support/larmkoder (all models listed on the page), checked 2026-11-03
- IVT – Larmkoder, ivt.se/support/larmkoder (all models listed on the page), checked 2026-11-03
- IVT – Larmkoder, ivt.se/support/larmkoder (all models listed on the page), checked 2026-11-03
- Fujitsu General – Troubleshooting Guide 2019 (manufacturer's service document), US models, table "Wall Mounted 9–36 (…RL/CL/RLS/RLX)"; Fujitsu – Fujitsu Trouble Shooting Guide (UK edition, undated, R22 era, 4 pages), p. 1 "Current Models" (wall-mounted ASY/ASYA/ASYB); lamp colours also in Fujitsu Error Codes – Air Conditioner Hardwired Remote Controller System Error Codes (publisher unknown, not a Fujitsu document, undated)
- Fujitsu General – Troubleshooting Guide 2019 (manufacturer's service document), US models, table "Multi-Zones"
- Fujitsu General – Troubleshooting Guide 2019 (manufacturer's service document), US models, table "AOU24RML, AOU24RML1, AOU36RML, AOU36RML1"
- Fujitsu – Fujitsu Trouble Shooting Guide (UK edition, undated, R22 era, 4 pages), p. 2 "Wired Remote Control Models" and p. 3 "Wired Controllers – Fault diagnostics"; Fujitsu General – Troubleshooting Guide 2019 (manufacturer's service document), US models, column "Wired Remote"; Fujitsu Error Codes – Air Conditioner Hardwired Remote Controller System Error Codes (publisher unknown, not a Fujitsu document, undated) (codes 00–09)
- Fujitsu Error Codes – Air Conditioner Hardwired Remote Controller System Error Codes (publisher unknown, not a Fujitsu document, undated); Fujitsu – Fujitsu Trouble Shooting Guide (UK edition, undated, R22 era, 4 pages), p. 3 "Wired Controllers – Fault diagnostics" and p. 4 code table
- Fujitsu – Fujitsu Trouble Shooting Guide (UK edition, undated, R22 era, 4 pages), p. 1 "Current Models" (left-hand table)
- Fujitsu – Fujitsu Trouble Shooting Guide (UK edition, undated, R22 era, 4 pages), p. 1 "Wall Mounted Multi Models"
- Fujitsu – Fujitsu Trouble Shooting Guide (UK edition, undated, R22 era, 4 pages), p. 2 "Outdoor PCB Fault Codes"
- Fujitsu – Fujitsu Trouble Shooting Guide (UK edition, undated, R22 era, 4 pages), p. 2 "Outdoor PCB Fault Codes"
- Fujitsu – Fujitsu Trouble Shooting Guide (UK edition, undated, R22 era, 4 pages), p. 2 "Outdoor PCB Fault Codes" (non-inverter)
- Fujitsu – Fujitsu Trouble Shooting Guide (UK edition, undated, R22 era, 4 pages), p. 2 "Inverter Multi AOY30"
- Fujitsu – Fujitsu Trouble Shooting Guide (UK edition, undated, R22 era, 4 pages), p. 3 (model references A–G) and p. 4 "Wireless Remote Control Models – Diagnostics"
- NTF – Technical Documentation, NTF ice makers families (SL, IC, CM, FRM/IW/DSS/ID, SLF/SLT, CVC/CV, GM/MGT, IFT, SM), 2019 (sections dated 2006–2018); GM360 Line, electric circuit and wiring diagram
- Staff – Operating and maintenance instructions, ice cream machines: batch freezers (IT/EN/SV, Swedish edition supplied by ABM AB), doc. 8000107710; ABM AB – Snabbguide för användande av STAFF BFX glassmaskiner (quick guide)
- Staff – Operating and maintenance instructions, ice cream machines: batch freezers (IT/EN/SV, Swedish edition supplied by ABM AB), doc. 8000107710
- Hitachi – Self-Contained Air Conditioners RUA-NP4ATS…RUA-NP10ATS (R410A), Installation, Operation and Maintenance Instructions Manual 65MP3197-A2 (Bosch Home Comfort Philippines); undated, PDF file created 2025
- NTF – Technical Documentation, NTF ice makers families (SL, IC, CM, FRM/IW/DSS/ID, SLF/SLT, CVC/CV, GM/MGT, IFT, SM), 2019 (sections dated 2006–2018); 'Linear ice makers series' service training slides, pages 104–135
- Fujitsu General – AIRSTAGE J-II Service Manual, small VRF system (R410A; outdoor units AJ*A36/45/54LALH), undated, ch. 4-2-4/4-2-5 (p. 04-06–04-07) and trouble shooting 1–11, 82–84 (p. 04-12–04-22, 04-79–04-81)
- Fujitsu General – AIRSTAGE J-II Service Manual, small VRF system (R410A; outdoor units AJ*A36/45/54LALH), undated, ch. 4-2-6 (p. 04-07) and trouble shooting 77–81 (p. 04-76–04-79)
- Fujitsu General – AIRSTAGE J-II Service Manual, small VRF system (R410A; outdoor units AJ*A36/45/54LALH), undated, ch. 4-1-1 and 4-2-1 (p. 04-01, 04-03)
- Fujitsu General – AIRSTAGE J-II Service Manual, small VRF system (R410A; outdoor units AJ*A36/45/54LALH), undated, ch. 2-6-1 (p. 02-11–02-12), 4-1-2, 4-2-2, 4-2-3 (p. 04-02, 04-04, 04-05) and trouble shooting 12–48 (p. 04-23–04-57)
- Fujitsu General – AIRSTAGE J-II Service Manual, small VRF system (R410A; outdoor units AJ*A36/45/54LALH), undated, ch. 4-3-3 (2), trouble shooting 59–64 (p. 04-65–04-67)
- Fujitsu General – AIRSTAGE J-II Service Manual, small VRF system (R410A; outdoor units AJ*A36/45/54LALH), undated, ch. 4-3-3 (3), trouble shooting 65–76 (p. 04-68–04-75)
- Fujitsu General – AIRSTAGE J-II Service Manual, small VRF system (R410A; outdoor units AJ*A36/45/54LALH), undated, ch. 4-3-3 (1), trouble shooting 55–58 (p. 04-63–04-64)
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