F7
Fujitsu Inverter Compressor Speed Control Error

Indoor unit shows F7, abnormal compressor speed control, unit may not reach set temperature

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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

Faulty inverter power module, Incorrect DC bus voltage, Compressor internal fault, Loose compressor connector

How to Fix / Troubleshooting

Safety first: Inverter circuits carry lethal voltages even after power is removed. Only qualified technicians should open the outdoor control box and test inverter components.

  • Homeowner checks:
    • Ensure outdoor unit has stable power supply (no frequent brownouts).
    • Verify outdoor coil and fan are clean and unobstructed.
  • Technician diagnostics:
    • Check DC bus voltage and AC input.
    • Measure compressor winding resistance and insulation.
    • Inspect inverter module for burn marks or cracked solder joints.
  • Likely repair: Replace the outdoor inverter PCB assembly if compressor tests good but F7 persists. If compressor is faulty, compressor and possibly outdoor unit replacement is required.
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Repair Difficulty

Professional Required 5/5

Required Part

Outdoor Inverter PCB
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