How to evacuate and (pulling vacuum on an R134a car AC system)

Follow the steps below and you will come to see the best result to your aiconditioning system.


1.Turn off the air conditioning in the car and switch off the car engine.

2.Hook up the refrigerant gauge manifold set. The pump hose should be attached to the low-pressure port of the refrigerant gauge. The hose is attached, in simplified terms, to the port that is found in the middle of the gauges. This step is very important in vacuuming the AC system. It helps maintain the vacuum even after the pump shuts down. Refrigerant can be added only after the correct level of vacuum is maintained.




3.Screw the AC vacuum pump to the center valve of the refrigerant gauge manifold set. Keep checking the gauge till the vacuum level reaches 27 Hg. Allow the pump to run for no less than 30 minutes.


4.Close the valve that goes to the gauge. Turn the pump to the off position. Leave the equipment in place, without running the pump for another 30 minutes. After this 30 minutes of idle time, check to see if the vacuum level remains at 27 Hg. If the level is less than 27Hg, then there is a leak in the system that needs to be fixed before moving to the next step.


5.Disconnect the pump hose from the pump and place in a can of refrigerant or freon after the proper of level of vacuum is present and there are no leaks detected. Start the car. Now, turn on the air conditioning system. Open the low-pressure manifold slowly to allow the refrigerant, usually Freon, to flow into the system.