Description
The Trane CNT03049 SPST Defrost Control Switch is a temperature activated safety unit used to regulate defrost operation in heat pump units in HVAC systems. It operates as an normally closed switch rated for 10A at 120 VAC, calibrated to open around 39F and reset near 55F based on coil conditions. It is installed in outdoor heat pump assemblies. It continuously monitors coil temperature and signals the control circuit when frost accumulation requires defrost mode activation. Its role is to maintain effective heat transfer, prevent ice buildup on the outdoor coil, and support consistent heating performance during cold weather operation.
