P0
Westinghouse DC Bus Voltage Protection / Inverter Power Supply Fault

Unit displays P0 and may not start compressor; fan may still operate.

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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 supply voltage, loose power connections, failed rectifier or DC bus capacitor, inverter PCB fault

How to Fix / Troubleshooting

Safety: High DC voltages are present on inverter boards. Only qualified personnel should work on live circuits.

User-level checks:

  • Verify supply voltage: Ensure the supply matches the unit rating and that there are no brownouts or surges.
  • Check breakers and wiring: Confirm breakers are not tripping and that power cables are secure and undamaged.
  • Power reset: Turn off power for 10 minutes, then restore and test. If P0 persists, stop using the unit.

Professional service: A technician should test the DC bus voltage, rectifier, and capacitors, and replace the inverter PCB if necessary.

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Repair Difficulty

Professional Required 5/5

Required Part

Outdoor Inverter PCB
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