Evacuating Refrigerant System

EVACUATING REFRIGERANT SYSTEM
1. When an A/C System has been opened to the atmosphere, such as during installation or repair, it must be evacuated using a vacuum pump. (If the system has been open for several days, the receiver/drier should be replaced).
2. Start the pump, then open both gauge valves. Turn the pump for about 15 minutes. Close the valves and stop the pump. The low gauge should indicate above 700 mm Hg (27 in-Hg) and remain steady with the valves closed.

NOTE
If low pressure does not reach more than 700 mm Hg (27 in- Hg) in 15 minutes, there is probably a leak in the system.
Check for leaks, and repair (see Leak Test below).

3. If there are no leaks open the valves and continue pumping for at least another 15 minutes, then close both valves and stop the pump.

LEAK TEST
1. Attach an Air Conditioning Service Station.
2. Open high pressure valve to charge the system to about 100 kPa (14 psi), then close the supply valve.
3. Check the system for leaks using a leak detector.
4. If you find leaks that require the system to be opened (to repair or replace hoses, fittings, etc.), release any charge in the system according to the Discharge Procedure.
5. After checking and repairing leaks, the system must be evacuated.