Overview
Leak detection and prevention is one of the most heavily regulated areas under the EU F-Gas Regulation 517/2014. Refrigerant leaks waste energy, damage the environment, and compromise system performance. Certified technicians must know when checks are required, which methods to use, and how to record and report their findings in compliance with EU Implementing Regulation 2015/2067.
Mandatory Leak Check Thresholds
The regulation bases check frequency on the CO₂ equivalent (CO₂e) charge of the system, not simply the kilogram charge:
- 5 to < 50 tonnes CO₂e — leak check at least every 12 months.
- 50 to < 500 tonnes CO₂e — leak check at least every 6 months.
- ≥ 500 tonnes CO₂e — leak check at least every 3 months, and an automatic leak detection system must be installed.
If an automatic leak detection system is fitted, the manual check interval is halved (e.g., 12 months becomes 24 months). The automatic system itself must be checked at least once every 12 months.
Direct Detection Methods
- Electronic leak detectors — capable of detecting leaks as small as 5 g/year. Must be calibrated and maintained according to manufacturer instructions.
- UV dye detection — a fluorescent dye is circulated with the refrigerant; leaks glow under UV light.
- Bubble testing — soapy solution applied to joints and fittings; bubbles indicate a leak. Effective but limited to accessible joints.
- Nitrogen standing-pressure test — the system is pressurised with OFN and monitored for pressure decay over time.
Indirect Detection Methods
Indirect methods use operating data to infer leakage:
- Monitoring superheat, subcooling, and suction/discharge pressures over time.
- Tracking energy consumption — a rise may indicate loss of charge.
- Comparing sight-glass condition — persistent bubbles in the liquid line suggest low charge.
These methods supplement but do not replace mandatory direct checks.
Follow-Up Obligations
- When a leak is detected it must be repaired without undue delay.
- A follow-up leak check must be carried out within one month of the repair to confirm the leak has been fixed.
- All checks — date, results, methods used, quantities added or recovered — must be recorded in the equipment logbook and retained for at least five years.
Exam Tip: Be able to calculate the CO₂e of a system and determine the correct check frequency. For example, a system with 8 kg of R-410A (GWP 2088) has a CO₂e of 16,704 kg = 16.7 tonnes, placing it in the 12-month check category. Exam questions often test this calculation and the effect of fitting an automatic detection system.
