When evacuating the system with both high and low side hoses connected to the compressor,
1.Open high side hand wheel on gauge manifold.
2.Leave low side hand wheel closed on gauge manifold. Start vacuum pump.
3.Observe low side gauge (should go into vacuum).
4.If it does not go into a vacuum reading, you have a restriction.
5.Continue operating till you have reached 29" hg. vacuum although using a micron gauge is the proper way (500 microns).
6.Let unit stand for 5 minutes, should be no change.
7.A slow rise indicates moisture (longer evacuation time).
8.Rapid rise, you got a leak.