Evacuating the System

Evacuating the System
1. Discharge the refrigerant system.
2. Make sure that the manifold gauge set is connected as follows:
a. Low pressure hose connected to low pressure service port on the receiver/drier.
b. High pressure hose to the high pressure service port on the compressor discharge line at the A/C condenser core.
c. Connect the gauge set center hose to a vacuum pump.
3. Open gauge set valves and start vacuum pump.
4. Evacuate system with the vacuum pump until the low pressure gauge reads at least 99.4 kPa (29.5 in. Hg) or vacuum and as close to 101 kPa (30 in. Hg) as possible. Continue the vacuum pump operation for a minimum of 15 minutes. If a part of the system has been replaced or excessive moisture is suspected, continue the vacuum pump operation for at least 30 minutes.
5. When evacuation of the system is complete, close the gauge set valves and turn the vacuum pump off.
6. Observe the low side gauge to be sure the system holds vacuum for five minutes. If vacuum is held for five minutes, proceed to charging the system. If vacuum is not held for five minutes, leak test the system, repair leak(s) and again evacuate the system.