Make sure the AccuProbe
™
IR leak detector is in SAE mode by holding the “MODE”
button for 5 seconds during startup. This sets the sensitivity levels outlined in the table
below:
1. Leak test with the engine off.
2. Charge the system with sufficient refrigerant to have a gauge pressure of at least
340 kPa (50 psi) with the system off. At ambient temperatures below 15 °C (59 °F)
leaks may not be measurable because the pressure may not be reached.
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 all fittings, hose-
to-line couplings, refrigerant controls, service valves with caps in place, brazed
or welded areas, and areas around attachment points and hold-downs on lines
and components. If looking for an apparently larger leak, check first at the 7 g/yr
Medium or 14 g/yr Low position.
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. Recheck service valves with caps removed. Blow shop air over service valve to clear
immediate area, and then check with detector on 7 g/yr Medium setting.
6. Move the detector at a rate of no more than 75 mm/sec (3 in/sec) and as close
as possible to 9.5 mm (3/8 in) from the surface, completely encircling each test
position (switch, sensor, refrigerant tubing connection, etc).
7. Slower movement and closer approach of the probe normally improves the likelihood
of finding a leak. However, detectors made to meet this standard are based on air
sampling from the 9.5 mm (3/8 in) distance. So retest is advisable when a leak
appears to be found at the most sensitive settings, particularly if the probe was in a
static position on a joint, or making physical contact with a joint, as it was moving.
Repeat with a moving probe test at that location, taking care to maintain the small
gap (9.5 mm or 3/8 in) to confirm that the leak is of repairable size. Use of the 7 g/yr
(0.25 oz/yr) Medium position of the detector, after finding an apparent leak with the
4 g/yr (0.15 oz/yr) High setting, also may be helpful.
LEAK TESTING OF MOBILE A/C SYSTEMS
R-1234yf Leak Rate (g/yr)
Sensitivity Setting
14
Low
7
Medium
4
High
3
