Manual

4. In windy areas, even a large leak can be difficult to find. Under these conditions, it is

best to shield the potential leak area from wind or breezes.

5. A leak is a constant source of refrigerant, and when a true leak source is located, it

should produce a repeatable alarm each time it is approached. Intermittent (non-

repeatable) alarms are often caused by accumulations of refrigerant near or around

leak points.

6. If an alarm occurs, and cannot be repeated when the probe tip is placed at the

same point again, it is unlikely there is a significant leak present at that point.

However, this may be indicative of a leak nearby – and can be used as a diagnostic

aid in leak finding.

SAE J1628 Recommended Procedure

NOTE: Leak test automotive A/C systems with the engine turned OFF.

1. The air conditioning or refrigeration system should be charged with sufficient

refrigerant to have gauge pressure of at least 340 kPa (50 psi) when not in

operation. At temperature below 15°C (59°F), leaks may not be measurable, since

this pressure may not be reached.

2. Do not contaminate the detector probe tip nor part being tested. If the part is

particularly dirty, or condensation (moisture) is present, clean it with a dry shop

towel or shop air. Do not use cleaners or solvents, since the detector may be

sensitive to their ingredients.

3. Visually trace the entire refrigerant system, and look for signs of air conditioning

lubricant leakage, damage, and corrosion on all lines, hoses, and components.

Check each questionable area with the detector probe, as well as fittings, hose-to-

line couplings, refrigerant controls, service ports with caps in place, brazed or

welded areas, areas around attachment points, and hold-downs on lines and

components.

4. Follow the refrigerant system around in a continuous path so no areas of potential

leaks are missed. If a leak is found, continue to test the remainder of the system.

5. At each area checked, move the probe around the location at a rate no more than

25 to 50 mm/second (1–2 inch/second), and no more than 5 mm (1/4 in.) from the

surface, and completely around the position. Slower and closer movement of the

probe greatly improves the likelihood of finding a leak (see Fig. 6). Any increase in

the alarm rate is indicative of a leak.

Fig. 6