Comfortmaker Defrost System Malfunction (Heat Pump)

Comfortmaker air conditioner frequently freezes the outdoor coil in heat pump heating mode

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Failed defrost sensor, Defective defrost control on outdoor board, Reversing valve not shifting properly, Low refrigerant charge

Safety: Turn off power at the disconnect before opening the outdoor unit.

Steps:

Observe defrost operation: In cold weather, the Comfortmaker heat pump should periodically enter defrost. If it never does, suspect defrost control issues.
Check defrost sensor: Ensure it is attached to the coil and test resistance vs. temperature.
Inspect board: Look for burned components on the outdoor control board.

Technician required: Defrost timing and refrigerant issues should be handled by a professional.

Hard 4/5

Defrost Control Board and Sensor

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