Which device is intended to limit refrigerant loss during relief events?

• A. Pressure relief valve
• B. Vent valve
• C. Fusible plug
• D. Check valve

Answer: (A)

Relief safety devices are designed to prevent overpressure and control how much refrigerant escapes during abnormal conditions. The pressure relief valve opens automatically at a set, safe pressure to vent refrigerant in a controlled way, preventing a violent release and keeping the loss to a minimum. It’s calibrated to release only as much as needed to bring pressure back down, rather than letting pressure rise unchecked.

A vent valve is used to purge air or non-condensables during service or startup; it’s not designed to automatically relieve overpressure events. A fusible plug provides a one-time safety release at very high temperature, which can lead to an uncontrolled loss rather than a controlled, limited vent. A check valve prevents backflow, but it does not relieve overpressure at all.