Installing a new defrost sensor often resolves this

providing a balance between responsiveness and false-trip prevention

Reduced Installation Time: Precise shaft length and diameter provide an exact match for standard Trane blower wheels

always verify your specific model's pressure differential requirements against Carrier service literature

The 51-42179-01 is a CCW (Counter-Clockwise) rotation motor when viewed from the lead end

Nordyne 669471R Coil 318820-201 Installing a new defrost sensorThe Nordyne 669471R is a high performance 24v reversing valve coil designed for precision operation in air conditioning and heat pump systems. This genuine OEM component is the direct replacement for part number EF19ZZ134, ensuring seamless integration into existing service workflows. Built to withstand the rigorous demands of HVAC 4 way valves, this coil handles the electrical shifting of the reversing valve to toggle between heating and cooling