AL14
FG Wilson
Incorrect Phase Rotation Detection
Controller shows AL14 – Phase Rotation / Wrong Phase Sequence
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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 alternator output cable connection, Reversed phases at ATS or load panel, Miswired sensing leads to controller
How to Fix / Troubleshooting
Safety first: Isolate the generator and lock out the output breaker. Verify that all sources are de-energized before touching power cables.
- Confirm phase sequence: Using a phase rotation meter at the generator terminals, verify that the phase order (e.g., L1-L2-L3) matches the site standard (usually ABC).
- Inspect cabling: Check that the generator output cables are correctly landed on the terminal block and match the wiring diagram. Correct any swapped phases.
- Check ATS wiring: At the automatic transfer switch, ensure the generator input phases are in the same order as the utility supply phases.
- Controller sensing: Verify that the controller's voltage sensing leads are connected to the correct phases and terminals.
- Retest: After corrections, clear the alarm and run the generator, confirming that the phase rotation alarm no longer appears.
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Repair Difficulty
Hard
4/5
Required Part
Generator Output Cable Set
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