R-12 Systems

The system must be completely discharged before evacuation. After discharging the system, keep low pressure gauge hose connected to low pressure test fitting and both manifold gauge valves closed.
1. Connect high pressure gauge hose to vacuum pump.
2. Connect center manifold gauge hose to refrigerant source with tapping valve closed.
3. Open high and low side gauge valves with vacuum pump operating.
4. Continue to operate pump for approximately 15-20 minutes after low side gauge reaches 29 or more inches of vacuum. If the system has been left open for any period of time, it should be partially charged, then evacuated again.
5. Close both gauge valves and turn vacuum pump off. Ensure vacuum does not drop more than 2 inches in 5 minutes. If vacuum does drop more than 2 inches, check all system connections for leaks and correct as necessary.
6. Open valve on refrigerant container and allow 14 ounces of refrigerant to enter system. Close refrigerant container and low pressure valve and recheck system for leaks. Repair as necessary.
7. Discharge refrigerant, then evacuate system. Do not discharge refrigerant through vacuum pump.
8. Operate vacuum pump for approximately 20 minutes at a minimum of 28 inches vacuum, then close both gauge valves and shutoff vacuum pump.