Refrigerant System Evacuate

NOTE: If the air-conditioning refrigerant system has been open to the atmosphere, it must be evacuated before the system can be charged with refrigerant. Moisture and air mixed with the refrigerant will raise the compressor head pressure above acceptable operating levels and will reduce the performance of the air-conditioner and damage the compressor. Moisture will boil at room temperature when exposed to vacuum. To evacuate the refrigerant system,

1. Connect a suitable charging station or manifold gauge set with vacuum pump.
2. Open the suction and discharge valves and start the vacuum pump. When the suction gauge reads 438 kPa (26 in. Hg) vacuum or greater, close all valves and turn off vacuum pump. If the system fails to reach specified vacuum, the refrigerant system likely has a leak that must be corrected. If the refrigerant system maintains specified vacuum for at least 30 minutes, start the vacuum pump, open the suction and discharge valves, and allow the system to evacuate an additional 10 minutes.
3. Close all valves, turn off, and disconnect the vacuum pump.

The refrigerant system is prepared to be charged with refrigerant.