Electronic Leak Detectors

Testing the refrigerant system for leaks is one of the most important phases of troubleshooting. One or more of the methods outlined will prove useful in detecting leaks or checking connections if service work is performed. Before beginning any leak test, attach a manifold gauge set and note pressure. If little or no pressure is indicated, a partial charge must be installed. Check all connections, compressor head gasket, oil filler plug and compressor shaft seal for leaks.

There are a number of electronic leak detectors available to perform leak tests. Current versions of the electronic leak have three settings, one for R-12, one for R-134a and one for gross. The gross setting is for isolating very large leaks already found in one of the other two settings. Refer to operating instructions for the unit being used and observe these general procedures.
1. Move detector probe one inch per second in areas of suspected leaks.
2. Position probe below test point, as refrigerant gas is heavier than air.
3. Be sure to check service access gauge port valve fittings, particularly when valve caps are missing, as dirt accumulations can destroy the sealing area of valve core when manifold gauge set is attached. Replace missing valve caps after cleaning valve core area.

NOTE: Valve caps should only be finger tightened. Using pliers to tighten valve caps may distort sealing surface of valve.

4. Check for leaks in manifold gauge set and hoses, as well as the rest of the system.