What is the purpose of isolating a parallel compressor when recovering refrigerant?

• A. To prevent reverse rotation of compressors
• B. Because of an open equalization connection
• C. To reduce noise
• D. To improve heat exchange

Answer: (B)

Isolating a parallel compressor during refrigerant recovery centers on preventing flow through the equalization line that connects the compressors. In parallel setups, the equalization connection balances pressures between compressors when they’re running. If you don’t isolate, the recovery unit can pull refrigerant and oil through that open equalization path into the other compressor, or allow refrigerant to migrate where it’s not being recovered. This makes recovery incomplete and can cause cross-flow issues or oil contamination. By isolating, you remove that unintended path, ensuring the recovery process pulls refrigerant from the intended circuit only.