Evacuate System

Specification for system pump-down used here is 28 - 29.5 inches vacuum. This reading can be attained at or near sea level only. For each 1000 feet of altitude, vacuum reading will be 1 inch lower. For example, at 5000 feet, only 23 - 24.5 inches of vacuum can be obtained. The system must be completely discharged before evacuation. Damage to vacuum pump may result if pressurized refrigerant is allowed to enter.

1. With gauges connected, remove cap from vacuum hose connector. Install gauge manifold center hose to vacuum pump connector. Open low side gauge manifold valve only.
2. Ensure low side gauge is calibrated correctly. It should be reading zero. If not, adjust calibration.
3. Evacuate system until low pressure gauge reads at least 28 inches of vacuum. Continue evacuating system for an additional 15 minutes for routine system servicing. If any parts have been replaced, evacuate for 20 to 30 minutes.
4. When system evacuation is complete, close low side gauge manifold hand valve and turn vacuum pump off.
5. Check ability of system to hold vacuum. Watch low side gauge to see that it does not rise faster than 1 inch vacuum every 4 to 5 minutes. if low side gauge rises too rapidly, install partial charge and leak test. Evacuate system again.
6. If system holds vacuum, charge system with refrigerant.