Refrigerant Migration Risk Assessment

Assess refrigerant migration risk during off-cycles based on conditions, heaters, and system design.

How long the compressor will be off. Longer off-cycles increase migration risk.
hours
If the compressor/crankcase is cooler than the evaporator or outdoor ambient, refrigerant migrates to it.
deg F
Different refrigerants have different solubility in oil, affecting migration severity.
Crankcase heaters keep the compressor warm to prevent liquid refrigerant from condensing in the oil.
Total refrigerant charge in the system. Larger charges mean more potential migration.
lbs
Pump-down systems store refrigerant in the receiver during off-cycle, greatly reducing migration.

Results

Migration Risk Level:
Overall risk assessment based on all factors. High risk can cause compressor damage on startup.
-
Est. Liquid Migration:
Estimated pounds of liquid refrigerant that could migrate to the compressor crankcase.
-lbs
Oil Dilution Risk:
Refrigerant dissolving in oil reduces lubrication and can cause bearing failure.
-
Recommendations:
Steps to mitigate refrigerant migration risk.
-
Reference: Emerson Climate Technologies Application Guide. Copeland Compressor - Crankcase Heater Guidelines.