Preliminary Information

The refrigeration system may be discharged, evacuated and charged using a commercial air conditioning charging station, or a manifold gage set, charging line adapters, vacuum pump, and a drum (or small cans) of Refrigerant-12. There are several methods of performing these procedures, varying primarily with the type of equipment used. The procedure described here is for manifold set gage, vacuum pump, and R-12 drum canister.

Important
^ Always wear safety glasses.
^ Wrap a clean cloth around fittings and connections when doing work that involves opening the refrigeration system. If liquid refrigerant comes in contact with skin or eyes, personal injury may occur.
^ Before removing or replacing any component or line, the system must be completely discharged.
^ Always use service valve and pressure sets during evacuation and charging procedures.
^ Always discharge system at the low-side service fitting.
^ Perform the entire charging and evacuation procedure through the low-side service fitting.

Connecting and Disconnecting Gages

CAUTION: Never remove a gage line from its adapter when the line is connected to the A/C system. To disconnect a line, always remove the line adapter from the service fitting. Do not remove a charging hose from the gage set while the hose is attached to the low-side service fitting. Doing so will cause the system to discharge completely because the Schrader-type valve on the fitting is depressed. This discharge may cause personal injury due to escaping Refrigerant-12.