Electronic Halogen Leak Detectors

Tool Required:
J 39400 Halogen Leak Detector

This type of leak detector has been found to be the most useful tool in locating refrigerant leaks. The J 39400 is a small unit which operates on 12 volts dc and provides an audible signal which increases in frequency when leaking refrigerant is detected. There are three settings: one for R-12, one for R-134a, and one for gross leaks. The gross leak setting is for isolating very large leaks already found at one of the other two settings. Care must be taken that the instrument is properly calibrated, per the included instructions, and that it is used at the proper setting for the type of refrigerant in the system being tested.

EVAPORATOR CORE

Because the evaporator core is contained in a closed module and is inaccessible to leak detectors, it is one of the most difficult parts of the air conditioning system to check for leaks. To leak-test the evaporator core:

1. Turn the blower motor on to high for 15 or more seconds then shut it off.
2. Wait 10 minutes.
3. Remove blower motor resistor.
4. Insert the leak detector probe into the resistor opening. If the detector goes to a solid alarm, a leak has been found.

COMPRESSOR AND BLOCK FITTING

1. Blow shop air behind and in front of the compressor clutch/pulley for at least 15 seconds.
2. Probe the compressor area. If the detector goes to a solid alarm, a leak has been found.