Evacuation and Charging
Charging From A Bulk ContainerTest equipment must be connected to the refrigerant system in order to make system tests. If a charging station is used, follow the instructions of the station manufacturer.
1. With manifold gauge set valves closed to center hose, disconnect the vacuum pump from manifold gauge set.
2. Connect the center hose of manifold gauge set to a refrigerant charging cylinder. If a charging station is used, follow the manufacturer's instructions.
3. Loosen center hose at manifold gauge set and open refrigerant charging cylinder valve. Allow refrigerant to escape in order to purge air and moisture from center hose. Then, tighten center hose connection at manifold gauge set.
4. Disconnect wire harness snap-lock connector from clutch cycling pressure switch and install a jumper wire across two terminals of connector.
5. Open manifold gauge set low side valve to allow refrigerant to enter system. Keep refrigerant cylinder in an upright position if vehicle low-pressure service gauge port is not on suction accumulator/drier or suction accumulator fitting.
6. When no more refrigerant is being drawn into system, start engine and set the control assembly for MAX A/C and HI blower.
Continue to add refrigerant to system until specified weight of R-12 is in system. Then, close manifold gauge set low-pressure valve and refrigerant supply valve.
7. Remove jumper wire from clutch cycling pressure switch snap-lock connector. Attach the connector to pressure switch.
8. Operate system until pressures stabilize to verify normal operation and system pressures.
9. In high ambient temperatures, it may be necessary to operate a high volume fan positioned to blow air through radiator and condenser. This will aid in cooling engine and prevent excessive refrigerant system pressures.
10. When charging is completed and system operating pressures are normal, disconnect manifold gauge set from vehicle. Install protective caps on service gauge port valves.
Charging From Small Cans
The refrigerant charge level of A/C systems currently being used is critical to optimum performance. Either an under-charge or an over-charge will adversely affect performance. Using small cans to charge these systems is not recommended because the charge level cannot accurately be controlled. A charging cylinder or a charging station is the only recommended method.