A discharge-line check valve primarily prevents which condition?

A discharge-line check valve primarily prevents which condition?

• A. Liquid refrigerant migrating back into the compressor head
• B. Backflow into the receiver
• C. Oil dilution
• D. Air entrainment

Answer: (A)

Discharge-line protection focuses on stopping reverse flow from the high-pressure discharge line back into the compressor. When the compressor stops or the system pressure drops, liquid refrigerant in the discharge line can try to flow backward toward the compressor head. If that liquid re-enters the compressor on the next start, it can cause slugging, hydraulic shock, and potential damage to the compressor’s cylinders and lubrication system. The discharge-line check valve is oriented to allow flow only away from the compressor and to close if backflow begins, preventing that liquid from returning to the compressor head. It doesn’t primarily address backflow into the receiver, oil dilution, or air entrainment, which are governed by other parts of the system and different issues.

Discharge-line protection focuses on stopping reverse flow from the high-pressure discharge line back into the compressor. When the compressor stops or the system pressure drops, liquid refrigerant in the discharge line can try to flow backward toward the compressor head. If that liquid re-enters the compressor on the next start, it can cause slugging, hydraulic shock, and potential damage to the compressor’s cylinders and lubrication system. The discharge-line check valve is oriented to allow flow only away from the compressor and to close if backflow begins, preventing that liquid from returning to the compressor head.

It doesn’t primarily address backflow into the receiver, oil dilution, or air entrainment, which are governed by other parts of the system and different issues.