What does a fusible plug do on the refrigerant side of a condenser?

• A. Relieves pressure
• B. Increases pressure
• C. Regulates temperature
• D. Stops refrigerant flow

Answer: (A)

Fusible plugs are safety devices for high‑pressure refrigerant vessels. On the condenser, they’re placed so that if the internal temperature or pressure rises beyond the design limit, the fusible alloy melts and creates an opening that relieves refrigerant, lowering pressure and preventing the condenser from failing. This is a one‑time safety relief, not a normal control device, so it doesn’t regulate temperature or continuously stop or restrict flow. After it operates, the plug and adjacent hardware must be replaced.