OVERVOLTAGE
Guardian
Generator Output Voltage Too High
Controller shows OVERVOLTAGE; output voltage measures significantly above nominal (e.g., above 130 V line-to-neutral on a 120 V system).
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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
Defective voltage regulator, Loose or damaged sensing leads, Incorrect wiring at control board, Faulty control board regulation circuit
How to Fix / Troubleshooting
Safety first: Open the generator main breaker immediately to protect connected loads. Place the controller in OFF. Do not reconnect loads until voltage is stable.
- Inspect voltage regulator wiring: Locate the Guardian automatic voltage regulator (AVR) in the control compartment. Ensure all spade connectors and plugs are tight and free of corrosion.
- Check sensing leads: Verify the voltage sensing wires from the stator to the AVR and control board are intact and not pinched or burned.
- Measure no-load voltage: With the main breaker open, start the generator and measure output voltage. If it remains high, the AVR is likely defective.
- Replace AVR: Shut down the unit, disconnect battery, and replace the AVR with the correct Guardian part number. Reconnect wiring exactly as labeled.
- Final test: Restart, verify correct voltage, then close the main breaker and monitor under load. If OVERVOLTAGE persists, the control board may require replacement by a technician.
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Repair Difficulty
Hard
4/5
Required Part
Automatic Voltage Regulator
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