Failure to isolate a parallel compressor system will cause an open equalization connection that will prevent refrigerant recovery.

• A. Venting
• B. Recovery
• C. Circulation
• D. Purge

Answer: (B)

Parallel compressor systems have an equalization connection that balances pressures when a compressor is off. If that equalization line isn’t isolated during refrigerant recovery, the refrigerant can flow through the open path instead of being drawn into and stored by the recovery equipment. That means the refrigerant isn’t captured properly, so recovery cannot be completed correctly. The key idea is recovery: you must isolate the parallel compressor’s equalization to ensure the refrigerant is actually recovered. Venting would release refrigerant to the atmosphere, circulation would move refrigerant around inside the system, and purge involves removing non-condensables, not capturing the main refrigerant.