Leak Check Interval Dispute on a Retrofitted Chiller
A building manager tells you their chiller 'doesn't need leak checks because it's under 5 tonnes of CO2 equivalent'. You inspect the label: the chiller contains 95 kg of R-134a (GWP 1430). It was retrofitted three years ago from R-22, and the retrofit paperwork is missing. There is a visible oil stain at a flange and the sight glass shows bubbles. The manager wants a written statement that no leak checks are required.
1. Calculate the CO2 equivalent and determine the leak-check obligations.
Read the worked answer
CO2 equivalent = charge (kg) × GWP = 95 × 1430 = 135,850 kg CO2e, i.e. about 135.9 tonnes CO2e.
This is far above the 5-tonne threshold the manager cited, so mandatory leak checks apply. At this charge level the equipment falls into the higher band requiring periodic leak checks at the prescribed frequency (and more frequent checks where a leak has been detected until it is repaired and verified). The presence of automatic leak detection can extend intervals under the rules, but there is no evidence of a functioning detection system here.
I would not provide a statement that no checks are required - that would be incorrect. I would set out the calculation, the applicable check frequency, and record it.
2. The oil stain and bubbles indicate a leak. What must happen next, and what do you record?
Read the worked answer
The oil stain at the flange and bubbles in the sight glass indicate a leak. Under the regulations a detected leak must be repaired without undue delay, and the repair must be verified by a follow-up leak check before normal intervals resume.
Actions:
- Confirm and locate the leak (electronic detector, soap solution, or OFN pressure test as appropriate).
- Repair the flange leak (new gasket/O-ring, correct torque).
- Recover refrigerant before opening the circuit; record quantity recovered.
- Evacuate, recharge by weight, and verify with a leak check.
- Record the leak, the repair, the verification, and the refrigerant added/recovered.
The missing retrofit paperwork should be reconstructed: the current refrigerant, the charge in kg, and the CO2 equivalent must be documented on the equipment record so future checks are based on correct data.