Carrier 38CQ660029 Defrost Relay 321702-401 permitting flow when energized and

permitting flow when energized and providing a positive shut-off when de-energized to maintain system pressure

Operating at 208 Volts

ensuring optimal evaporator efficiency and compressor protection

Direct Swap Compatibility: Engineered as a drop-in replacement head mechanism for McDonnell & Miller Series 93 and 193 controls

For technicians performing maintenance or repairs

Carrier 38CQ660029 Defrost Relay 321702-401 permitting flow when energized andThe Carrier 38CQ660029 Defrost Relay is a specialized HVAC defrost control board designed for heat pump systems requiring precise field selectable timing. This genuine OEM replacement part manages the transition between heating and defrost modes by monitoring the defrost thermostat and cumulative compressor run time. Engineered for 208 240V configurations, the board supports a 10A current capacity and features adjustable intervals of 30, 45, or 90