Leak Detection

Leak Test

- A high proportion of all air conditioning work will consist of locating and repairing leaks. Many leaks will be located at connections and are caused by vibration. They may only require the retightening of a connection or clamp. Occasionally a hose will rub on a structural part of the vehicle and create a leak, or a hose will deteriorate which will require a replacement. The specified maximum leakage rate at each fitting is 0.5 kg of R12 in 40 years and a leak detector capable of operating to this accuracy must be provided.

- To check, place the leak detector probe at the lowest point of each joint, pause for two seconds. DO NOT wave the probe about as refrigerant is heavier than air and will flow to the lowest point. If a leak greater than 0.5 kg in forty years is detected, identify the leak point for rectification.

- Check that the leaking fitting has been tightened to the correct torque. If the torque is low, rectify and repeat leak test. If the torque is satisfactory, depressurize the system, dismantle the leaking connection and check the quality of the fitting.

- If the fitting is satisfactory, clean and reassemble after applying a thin film of refrigerant to the seat of a flare fitting, or a new oiled "0"ring to an "0"ring fitting. Tighten to the correct torque.

- Charge the system with 200 g of R12 and leak test the rectified system. If the system is satisfactory, depressurize, evacuate, and recharge the system. If the system is unsatisfactory, i.e. leakage greater than 0.5 kg in forty years, depressurize and replace the leaking assembly.