Inability to reach and hold 29 inches of mercury may indicate either a leak or a
problem with the vacuum pump.
(7) Close service manifold vacuum valve and stop vacuum pump. Note reading on compound gage and
observe for 10 minutes. If pressure rises, moisture may still be in the system or a leak exists. If pressure
rose, repeat evacuation and re- check. If the pressure rise occurs again at the same speed, a leak is in the
system and must be found per paragraph 5.7. If the pressure rise was slower the second time, moisture
remains in the system and the evacuation process must be repeated until there is no rise.
(8) Close service manifold high pressure gage and compound gage valves.
(9) Disconnect the v cuum hose from vacuum pump.
5.9 CHARGING THE REFRIGERANT SYSTEM.
THIS TASK COVERS
a. Full Charge
b. Partial Charge
Dangerous chemical refrigerant under pressure is used in the operation of this
equipment. Use great care to avoid contact with liquid refrigerant.
Sudden and irreversible tissue damage can result from freezing. Wear gloves and
a face protector or safety glasses in any situation where skin or eye contact with
refrigerant is possible.
Heat may cause the refrigerant to decompose and release irritating, toxic, and
corrosive gases. Prevent contact of refrigerant with flame or hot surfaces.
Never introduce high discharge pressure into a refrigerant cylinder.
cause the cylinder to rupture and injure personnel.
The system must be evacuated before charging. Moisture in the system will
prevent the refrigeration unit from operating properly.
(3) Connect the charge hose to a tank containing refrigerant R-134a set to deliver gas and the vacuum hose to