What effect does applying heat with a heat gun to a compressor have during recovery?

Applying heat with a heat gun to a compressor during the recovery process primarily serves the purpose of helping to vaporize any trapped liquid refrigerant. When refrigerant is in a liquid state, it takes up less volume and can remain trapped within the compressor. By applying heat, you increase the temperature of the compressor and the refrigerant inside, facilitating the conversion of liquid refrigerant to vapor. This change in state allows for more efficient refrigerant recovery, as vapor can be more easily evacuated from the system compared to liquid.

This process is particularly important during recovery because removed liquid refrigerant can otherwise cause issues, such as liquid slugging in recovery equipment, which can damage pumps and require additional service. Thus, heating the compressor is a practical and effective technique for ensuring that all trapped refrigerants can be properly and safely removed from the system.