TM 5-3805-298-23-4
0405
EVACUATION CONTINUED
000405
NOTE
At high elevations, less vacuum is required. 28 to 29 in.Hg (95 to 98 kPa) is required
specification at sea level. For every 1,000 ft (305 m) above sea level, decrease required
specification by 1 in.Hg (3 kPa).
AMBIENT TEMPERATURE
VACUUM REQUIRED TO BOIL WATER IN AC
0405
SYSTEM
0405
100F (38C)
28 in.Hg (95 kPa)
90F (32C)
28.5 in.Hg (96.5 kPa)
81F (27C)
28.8 in.Hg (97.5 kPa)
70F (21C)
29.2 in.Hg (98.8 kPa)
Evacuation procedure removes air and moisture from A/C system. Do not use evacuation
procedure primarily to indicate A/C system leak.
4. Evacuate A/C system until low pressure gauge indicates vacuum between 28 and 29 in.Hg (95 and 98 kPa).
a. If specific vacuum cannot be reached, A/C system may have leak. Repair all leaks and repeat steps 1
through 4.
b. If specific vacuum can be reached, continue to evacuate A/C system for minimum of 30 minutes and then
proceed to Step 5.
NOTE
Excessive vacuum loss is an indication of possible leak in A/C system.
Amount of vacuum loss in 5 minutes must not exceed 2 in.Hg (7 kPa).
5. If vacuum loss exceeds 2 in.Hg (7 kPa) in 5 minutes, repair all leaks and repeat steps 1 through 5. If vacuum
loss does not exceed 2 in.Hg (7 kPa) in 5 minutes, A/C system is ready to charge.
END OF TASK
0405-6
