10-21. AIR CONDITIONING SYSTEM SERVICING (M1010) (Cont).
When low side gage (2) needle stabilizes at 29 in. Hg, operate vacuum pump (11) for an
additional 30 minutes. Completely close low side valve (1) and high side valve (4) on manifold
gage set. Close discharge valve on vacuum pump, Wait 5 minutes, and check to see if low
side gage needle moves. If low side gage needle moves, there is a leak in air conditioning
system. Locate leak, if present, using refrigerant gas leak detector. Repair leak in system if
present, and repeat this step before performing step 4.
If low side gage (2) needle position remains constant, disconnect center hose (6).
c. CHARGING SYSTEM
l Never Open high side valve (4) on air conditioner manifold gage set
while air conditioning system is operating. Refrigerant may be pumped
back into refrigerant container (12) and cause refrigerant container to
explode, resulting in serious Injury or death to Personnel.
l Never attempt to charge system on the high side while air conditioning
system is running. Failure to follow this warning may result in injury to