Leak check of refrigeration systems: F-gas intervals and steps

EU · Step-by-step guide

Leak check step by step: intervals of 12, 6 or 3 months by tonnes CO2e, records, direct and indirect methods, EN 14624 detectors and the follow-up check after a repair.

Last checked: October 29, 2026Last changed: October 29, 2026 – The check after a repair is made after at least 24 hours of operation and within one month.

Key points

The interval depends on the charge in tonnes CO2e: 12, 6 or 3 months, twice as long with a leakage detection system ^[1].
The check is carried out by a certified person. It starts with the records and continues with an examination of the whole system ^[1].
An electronic leak detector must be calibrated and detect at least 5 g/year according to EN 14624 ^[3].
A leak must be repaired without undue delay and followed up with a new check at the earliest after 24 hours of operation and at the latest one month after the repair ^[1].
The old standard requirements in (EC) 1516/2007 have been repealed. Follow good practice and the manufacturer's instructions ^[2].

Before you start

Leak checks under the F-gas Regulation must be carried out by a person certified for the work ^[1]. Find out the system's refrigerant, charge and whether it has a leakage detection system, and work out the interval. The GWP calculator converts kilograms to tonnes CO2e and shows the interval. Check that the tools work: an electronic leak detector intended for the refrigerant that has been calibrated, leak detection fluid, gauges or digital instruments and thermometers.

Electronic leak detectors for halogenated refrigerants are tested according to EN 14624. According to the 2020 edition the sensitivity must be at least 5 g per year, and the instrument must be checked regularly against a calibrated reference leak ^[3]. For flammable refrigerants and for CO2, a leak detector intended for that particular refrigerant is required.

Step 1: Go through the records

Are there records, and do the refrigerant and charge match the nameplate on the unit?
When was the last check carried out, and was the result without remarks?
Has refrigerant been added since the last check? Additions without a known cause suggest a leak.
Are earlier leaks documented, and have the follow-up checks been carried out?
If a leakage detection system is required or installed: has it been checked in the past year?

Step 2: Inspect the system visually

Go through the whole system, not just the unit. Look for oil stains, which often show where refrigerant leaks, corrosion, chafed or vibrating pipes, loose pipe clamps, damaged insulation and damage to capillary tubes. Be extra careful at joints, flanges, flare fittings, valve stems and service valves, safety valves, pressure switches, compressor seals and the penetrations of the heat exchangers.

Step 3: Search for leaks with a direct method

A direct method means looking for the leak itself. Move the leak detector probe slowly, about 2–5 cm per second and as close to the surface as possible, around all joints and components. Start high and work downwards for refrigerants that are heavier than air, and switch off fans that spread the gas if possible. Confirm an indication with leak detection fluid: bubbles show exactly where the leak is. Check the low-pressure side when the system is at standstill, because the pressure there is higher at standstill.

Step 4: Check with indirect methods

Indirect methods show that something is wrong without pinpointing the leak. Compare operating data with earlier values at similar operating conditions: pressures and saturation temperatures, superheat and subcooling, the level in the sight glass or liquid level sensor, compressor current and temperatures. Low subcooling, bubbles in the sight glass at full load, high superheat or a falling liquid level can mean that refrigerant is missing. Deviations must be followed up with a direct method.

Step 5: Repair and document

A leak must be repaired without undue delay ^[1]. If the circuit has to be opened: recover the refrigerant with a recovery unit, repair, pressure test and tightness test, evacuate and charge.
Record in the logbook: the date, who carried out the check and their certificate number, the method, the result, where the leak was, what was done and the quantity of refrigerant added or recovered.
Plan the follow-up check. It must be carried out at the earliest after 24 hours of operation and at the latest one month after the repair, and show that the repair was effective. For some mobile equipment (Article 5(3)(a)–(c)) it may be done directly after the repair ^[1]. In Sweden a leak check is also required in connection with installation, conversion or other work on the system (Ordinance 2016:1128, Section 10), unless it is stationary hermetically sealed equipment under 5 t CO2e ^[5].
Give the information to the operator. In Sweden it is needed for the annual report to the supervisory authority by 31 March ^[4].

Common mistakes

Checking only the unit and missing evaporators, pipework and valves out in the plant.
Using a leak detector that is not calibrated or not intended for the refrigerant.
Adding refrigerant without finding and repairing the leak.
Forgetting the follow-up check or the entry in the logbook.

The standard requirements for leak checks used to be in Commission Regulation (EC) No 1516/2007. It was repealed without replacement by Implementing Regulation (EU) 2026/1444 of 2 July 2026 ^[2]. The methods above are based on good practice. Always follow the manufacturer's instructions and national rules.

Calculate it yourself

GWP, ODP & CO2e of a refrigerant charge →Troubleshooting: refrigeration and heat pumps →

Terms in this article

Leak check Leakage detection system CO2 equivalent (CO2e)Operator Hermetically sealed equipment Safety valve Sight glass