Display shows F8 and unit may shut down or limit capacity

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

Severely restricted airflow, Dirty evaporator coil, Blower motor failure, Incorrect fan speed settings, Faulty coil temperature sensor

Safety: Turn off power to the indoor unit.

Steps:

Replace air filter: Install a clean filter.
Inspect evaporator coil: Clean coil if dirty using appropriate coil cleaner.
Verify blower speed: Check Comfortmaker board dip switches or setup for correct CFM per ton.
Check blower motor: Ensure motor runs smoothly and at full speed.
Inspect coil sensor: Confirm it is properly attached and test resistance if accessible.

Technician required: If F8 persists, further diagnostics on airflow and sensor/board are needed.

Hard 4/5

Evaporator Coil Temperature Sensor (Thermistor)

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