York S1-031-01976-000 Control Board 30067439-890 Prevents Thermal Shock: Maintains a

Prevents Thermal Shock: Maintains a steady 140-degree setpoint to safeguard cast iron and steel heat exchangers from rapid temperature fluctuations

Using it in steam applications may result in component failure

If your multimeter reads below 20mV during an open-circuit test

Does this wheel include the setscrew for installation

Common Questions: Why is my Reznor unit heater short cycling

York S1-031-01976-000 Control Board 30067439-890 Prevents Thermal Shock: Maintains aThe York S1 031 01976 000 Defrost Control Board is a critical OEM replacement part engineered specifically for York, Luxaire, and Coleman heat pump systems. Designed to manage the precise timing and termination of the defrost cycle, this HVAC control module prevents excessive ice accumulation on the outdoor coil, preserving system efficiency during low ambient operation. Unlike universal boards, this York heat pump defrost board integrates seamlessly