Heat pump heater displays E04 and stops; this may occur in cold, humid conditions.

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

Defrost sensor failure, Sensor not properly attached to the coil, Control board defrost logic error, Excessive ice buildup on the evaporator

Safety first: Turn off power before working near the fan and coil.

Inspect for ice: Check the outdoor coil for heavy ice buildup. If present, allow the unit to defrost naturally by turning it off until the ice melts.
Check defrost sensor: Ensure the sensor is firmly clipped to the correct location on the coil and that its wiring is intact.
Clear airflow obstructions: Remove any objects blocking airflow around the unit.

If E04 persists, the defrost sensor or control board may need replacement by a technician.

Hard 4/5

AstralPool Defrost Sensor

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