Refrigerant Charging: Evacuation

Open all the valves of the manifold gauge.
CAUTION:
- Close the manifold gauge valve immediately after stopping the vacuum pump. If the valve is left open, the vacuum pump oil will back flow into the refrigeration cycle and cause a decrease in the efficiency of the air conditioner.
Start the vacuum pump and let it operate for 15 min .

Fig 1: Opening Valves Of Manifold Gauge
Verify that high- and low-pressure side readings of the manifold gauge are at -101 kPa {-760 mmHg, -29.9 inHg} . Close each valve of the manifold gauge.

Fig 2: Closing Valve Of Manifold Gauge