Using Vacuum Pump

Keep all R-134a components capped to prevent moisture from entering the system. If the refrigerant system has been opened to the atmosphere, it must be evacuated.
The system must be completely discharged before it can be evacuated. Damage to the vacuum pump may result if pressurized refrigerant is allowed to enter.
1. Connect suitable charging station, refrigerant recovery machine and a manifold gauge set with vacuum pump.
2. Open suction and discharge valves and start vacuum pump. The vacuum pump should run a minimum of 45 minutes before charging to eliminate all moisture in system. When suction gauge reads 26 inch Hg or greater for 45 minutes, close all valves and turn off vacuum pump. If system fails to reach specified vacuum, refrigerant system likely has a leak that must be corrected. If refrigerant system maintains specified vacuum for at least 30 minutes, start vacuum pump and open discharge and suction valves, and allow system to evacuate for an additional 10 minutes.
3. Close all valves, turn off and disconnect pump and charge with refrigerant.