F9
Haier Indoor-Outdoor Coil Temperature Difference Abnormal / Sensor Correlation Error

Indoor unit shows F9 and may not control temperature correctly; defrost or protection cycles may be abnormal.

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Safety Warning

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.

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Possible Causes

Incorrectly installed sensors, One or more NTC sensors out of calibration, Poor thermal contact between sensor and coil, Faulty indoor or outdoor PCB interpreting sensor data

How to Fix / Troubleshooting

Safety first: Disconnect power before touching sensors or coils.

  • Check sensor mounting: Ensure all coil sensors (indoor evaporator, outdoor condenser, discharge pipe) are firmly attached to the correct pipes and coils.
  • Inspect insulation: Replace any missing insulation around sensors to ensure accurate readings.
  • Compare sensor resistances: A technician can measure resistance of each NTC at the same temperature and compare to Haier's specifications.
  • Replace suspect sensors: If one sensor reads significantly different from others at the same temperature, replace it with the correct Haier part.
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Repair Difficulty

Hard 4/5

Required Part

Temperature Sensor Set (Indoor and Outdoor)
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