Leak Testing - Refrigerant System

The propane torch Halide Leak Detector is the most widely used of the detection devices. Therefore, only the procedure for this device will be given. The procedure is the same for any electronic detector, except that the pickup device registers the presence of refrigerant by a flashing light or high pitched squeal instead of changing the color of the flame. All other steps in preparing the system and leak testing are the same and can be followed as outlined below:
1. Stabilize system at 1500---1750 RPM. If system is empty of refrigerant, it will be necessary to install a partial charge before continuing. With gauges connected into system, adjust A/C controls for maximum cooling. Operate for 10 to 15 minutes, then shut "OFF" car engine.
2. Light leak detector. Open valve to a low flame that will not blow itself out. Warm up until copper element turns cherry red. Lower flame until flame tip is even with or slightly below center of element. For electronic tester, follow preparation procedure as given in operating instructions.
3. Move leak detector pickup under hoses, joints, seals, and any possible place for a leak to occur. R-12 refrigerant is heavier than air and will move downward. If concentration of refrigerant is located, move pickup upward to locate leak. Do not inhale fumes produced by burning refrigerant.
4. Watch for color change of flame: Pale blue, no refrigerant; yellow, small amount of refrigerant; purplish-blue, large amount of refrigerant. Repair system as necessary if leaks are located.
5. Check sensitivity of reaction plate: Pass pickup hose over empty can or crack open refrigerant container; flame should show violent reaction. If no color change, replace reaction plate, following instructions accompanying leak detector. Too high a flame will shorten life of reaction plate, and poor reaction and will soon burn out element.
6. Charge system if repairs were necessary.