Electronic Halogen Leak Detectors

Electronic Leak Detector:

Leak Testing In Line Connection:

Leak Testing Service Port:

Leak Testing Pressure Switch:

Tools 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 as R-134a is detected. Care must be taken that the instrument is properly calibrated, per the instructions included with the unit, and that the detector is used in the proper setting for the type of refrigerant being tested. The detector gas switch should be placed in R-134a setting prior to use.

The most common leaks are found at the refrigerant fittings or connections. This may be caused by improper torque, damaged O-rings, lack of lubricant on O-rings, or dirt/debris across the O-ring. Even the smallest piece of lint from cotton gloves or shop cloths can create a leak path across an O-ring.

The successful use of J 39400 or any other electronic leak detector depends greatly upon the scan rate and upon carefully following the manufacturer's instructions regarding calibration, operation and maintenance.

During testing, each joint must be circled completely, moving the detector probe at 51 mm (1-2 in) per second with the tip of the probe as close to the surface as possible, but no more than 6 mm (0.25 in) away and without blocking probe tip air intake. A leak is indicated when the audible tone goes from a steady 1-2 clicks per second to a solid alarm. The balance knob should be adjusted frequently to maintain the 1-2 clicks per second rate.

Important
- Halogen leak detectors are sensitive to windshield washing solutions, many solvents and cleaners, and some adhesives used in the vehicle. Care should be taken to prevent a false warning by making sure surfaces are clean. Also, surfaces should be dry since ingestion of liquids will damage the detector.
The evaporator inlet and outlet, accumulator inlet and outlet, condenser inlet and outlet, all brazed and welded joints, compressor rear head, and housing joints may be tested using this procedure.

Important
- Always follow the refrigerant system around in a continuous path so that no areas of potential leaks are missed.. Always test all the above areas to assure the entire system is leak free, even when one leak is already found.

CAUTION: Care should be taken to avoid personal Injury which could occur due to touching a hot engine during testing. Test should be done with the engine OFF and as cool as possible. Do not operate the detector in a combustible atmosphere since Its sensor operates at high temperature.