H1
Fujitsu Indoor-Outdoor Addressing or Capacity Mismatch Error

Indoor unit shows H1, unit may not start compressor

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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

Incorrect indoor unit model connected to outdoor unit, DIP switch or address setting mismatch, Incorrect wiring between multi-split indoor units and outdoor unit, Faulty communication PCB

How to Fix / Troubleshooting

Safety first: Turn off all power to the system before opening any electrical covers.

  • Verify model compatibility: Check that the indoor and outdoor unit model numbers are approved to work together per Fujitsu documentation.
  • Check address settings: On multi-split systems, verify that indoor unit address DIP switches or rotary selectors are set correctly and uniquely for each indoor unit.
  • Inspect wiring: Confirm that each indoor unit is wired to the correct terminals on the outdoor unit according to the wiring diagram.
  • Reset system: After correcting any settings, power down the entire system for 5 minutes, then restore power and test.
  • Technician involvement: If H1 persists, a technician may need to reprogram or replace the communication PCB.
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Repair Difficulty

Hard 4/5

Required Part

Indoor-Outdoor Communication PCB
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