ATP ZX-1A Heated Pentode Manuel De L'utilisateur page 12

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. Remember that a leak is a constant source of refrigerant and therefore 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 is not repeated when the probe tip is replaced to the same point, it is
unlikely that there is any 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: On Automotive A/C Systems leak test with the engine not in operation.
1. The air conditioning or refrigeration system should be charged with sufficient refrigerant to
have gauge pressure of at least 340 kPa (50psi) when not in operation. At temperature below
15ºC (59ºF), leaks may not be measurable, since this pressure may not be reached.
2. Take care not to contaminate the detector probe tip and that the part being tested is not
contaminated. If the part is particularly dirty, or condensation (moisture) is present, it should
be wiped off with a dry shop towel or blown off with shop air. No cleaners or solvents should
be used, 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. Each questionable
area should be carefully checked with the detector probe, as well as fittings, hose to line
couplings, refrigerant controls, service ports with caps in place, brazed or welded areas, and
areas around attachment points and hold-downs on lines and components.
4. Always follow the refrigerant system around in a continuous path so that no areas of potential
leaks are missed. If a leak is found, always continue to test the remainder of the system.
5. At each area checked, the probe should be moved around the location, at a rate no more
than 25 to 50 mm/second (1-2 in/second), and no more than 6.35mm (1/4 in.) from the sur
face, 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 beep rate is indicative of
a leak.
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FIG 6