F7
Chigo
Phase Loss / Phase Sequence Error (Three-Phase Models)
Indoor unit shows F7 and the system may not start or may shut down unexpectedly.
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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 phase sequence on three-phase Chigo outdoor unit, Missing phase from power supply, Loose or burnt terminal connections, Faulty phase detection circuit on outdoor PCB
How to Fix / Troubleshooting
Safety first: Three-phase systems carry dangerous voltages. Only licensed electricians or HVAC technicians should work on them.
- Step 1 – Verify supply phases: Have an electrician measure voltage between all three phases and confirm all are present and balanced.
- Step 2 – Correct phase sequence: If the phase order is wrong, swap any two phases at the main disconnect to correct rotation, following local codes.
- Step 3 – Tighten terminals: With power off, tighten all terminal screws in the outdoor unit and disconnect.
- Step 4 – PCB check: If supply is correct but F7 persists, the outdoor main PCB phase detection circuit may be faulty and require replacement.
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Repair Difficulty
Professional Required
5/5
Required Part
Outdoor Main PCB
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