Refrigerant Circuit, Tracing Leaks Using Electronic Leak Detector (For Example, V.A.G 1796): Notes
The various refrigerants have differing molecular compositions. The electronic leak detector sensors are set up to detect these molecules. If an electronic leak detector is used, which is not specifically designed to detect refrigerant R134a, it will not respond to the refrigerant R134a or will only do so when there is a larger concentration of R134a in the area of the leak.
Depending on the version of the A/C unit, an evaporator leak can be determined either by holding the leak detector test probe over the glove compartment cooling connection in the A/C unit, or by holding the test probe on an open connection of a disconnected A/C condenser water drain.
Perform a leak detection test to locate the leak while the refrigerant circuit is completely empty:
To prevent more refrigerant than is necessary for the leak test from venting into the air, proceed as follows with the refrigerant circuit completely empty:
-- Evacuate the refrigerant circuit with the A/C service station. Refer to Refer to REFRIGERANT CIRCUIT, EVACUATING WITH A/C SERVICE STATION .
If a larger leak is found during evacuation, find and it and repair it as described. Refer to Refer to REFRIGERANT CIRCUIT, EVACUATING WITH A/C SERVICE STATION .
If no leak is found during evacuation or there is a leak that is so small that the location cannot be found with the vacuum test, proceed as follows.
-- Fill the evacuated refrigerant circuit with approximately 100 grams of refrigerant and perform the leak test in the same way as for a refrigerant circuit that is filled with refrigerant. Refer to Perform a leak detection test on a refrigerant circuit that is filled with refrigerant: .