1. Leak detection and testing
Oil traces and excessive superheat can signal leakage. Leak test repaired equipment before charging. Use dry nitrogen with a regulator and relief valve—never oxygen or compressed air.
2. Recovery sequence
Recover liquid first when practical, then vapor. A cooler recovery cylinder, warmer appliance, short large-diameter hoses, and appropriate equipment capacity can improve speed.
3. Standing vacuum check
After reaching the required endpoint, isolate and wait. Pressure rebound may show refrigerant remains in oil or liquid pockets.
4. Equipment limits
Portable system-dependent recovery equipment generally cannot be used on appliances containing more than 15 pounds unless permanently attached as a pump-out unit.
5. Pressure and components
Understand psig versus psia, receivers, accumulators, liquid and vapor locations, and pressure-temperature data for refrigerant identification.
6. Safety
Do not energize a hermetic compressor under vacuum. Protect equipment rooms against oxygen deprivation. Verify retrofit approval and system compatibility instead of assuming a refrigerant is a drop-in.