Less vacuum is required at high elevations. At sea level, 28 to 29 inHg (95 to 98 kPa) of
vacuum is required. For every 1,000 ft (305 m) above sea level, the required specification
decreases by 1 inHg (3 kPa).
VACUUM REQUIRED TO BOIL WATER
IN A/C SYSTEM
28 inHg (95 kPa)
28.5 inHg (96.5 kPa)
28.8 inHg (97.5 kPa)
29.2 inHg (98.8 kPa)
Evacuation procedure removes air and moisture from A/C system. Do not use evacuation
procedure primarily to detect an A/C system leak.
4. Evacuate A/C system until low-pressure gauge indicates a vacuum of 28 to 29 inHg (95 to 98 kPa).
a. If specific vacuum cannot be reached, the A/C system may have a leak. Detect and repair all leaks and
repeat steps 1 through 4.
b. If specific vacuum can be reached, continue to evacuate A/C system for at least 30 minutes, and then
proceed to step 5.
Excessive vacuum loss indicates a possible leak in A/C system.
Amount of vacuum loss in 5 minutes must not exceed 2 inHg (7 kPa).
5. If vacuum loss exceeds 2 inHg (7 kPa) in 5 minutes, repair all leaks and repeat steps 1 through 5. If vacuum
loss does not exceed 2 inHg (7 kPa) in 5 minutes, A/C system is ready to charge.
END OF TASK