F1
Fujitsu High Pressure Protection / Overcharge or Airflow Fault

Indoor unit shows F1, unit may stop during heavy load conditions

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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

Blocked or very dirty outdoor condenser coil, Overcharged refrigerant system, Failed outdoor fan motor, Faulty high-pressure sensor or transducer

How to Fix / Troubleshooting

Safety first: Turn off power before cleaning coils or working near the fan. High-pressure refrigerant is hazardous; only technicians should connect gauges or adjust charge.

  • Clean outdoor coil: Remove leaves and debris from around the outdoor unit. Gently wash the coil from inside out with low-pressure water, avoiding bending fins.
  • Check outdoor fan operation: Restore power and observe the outdoor unit. Ensure the fan starts promptly and runs at normal speed. If not, see fan motor diagnostics (E7).
  • Ensure clearance: Maintain at least 12–24 inches of clearance around the outdoor unit for proper airflow.
  • Technician tasks:
    • Check system pressures and compare to Fujitsu charts.
    • Correct any overcharge or non-condensable gas issues.
    • Test and replace the high-pressure sensor if readings are abnormal.
  • Do not vent refrigerant: Never attempt to release refrigerant to the atmosphere; this is illegal and dangerous.
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Repair Difficulty

Hard 4/5

Required Part

Outdoor Condenser Coil
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