Error Code PC04 in Air Conditioners

The error code PC04 indicates an anomaly in the control of the inverter compressor. This issue is detected by a specialized circuit that monitors various factors, including:

• Communication signals.
• Voltage detection.
• Compressor rotation speed.

Below are the possible causes of error code PC04:

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Possible Causes of Error Code PC04

1. Wiring issues: incorrect or loose connections.
2. Failure of the Intelligent Power Module (IPM).
3. Failure of the outdoor fan motor.
4. Compressor malfunction.
5. Faulty PCB (printed circuit board) in the outdoor unit.
6. Overvoltage or current spike.
7. System blockage.
8. Inverter compressor controller error.

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Steps to Resolve Error Code PC04

1. Check the wiring:
   • Ensure the wiring of the outdoor unit, the main PCB, and the IPM board is correct and has no loose or faulty connections.
2. Measure the compressor voltage:
   • Use a multimeter to measure the compressor’s supply voltage at startup and during the fault.
   • The voltage should range between 310 V and 330 V when the compressor starts.
   • If the voltage significantly differs, inspect the connections on the IPM module board.
3. Verify the reactor resistance:
   • Check the wiring and measure the resistance between the respective reactor pins.
   • Normal resistance should be approximately 0.1 Ohm.
   • Also, measure the resistance between any pin and the metal casing of the outdoor unit, which should be infinite.
4. Inspect the electronic expansion valve (if applicable):
   • Check the wiring and measure the resistance of the valve.
5. Check refrigerant pressures:
   • Ensure the refrigerant pressures are within the correct range.
6. Inspect the compressor’s sleeve:
   • The compressor’s sleeve is a protective covering that surrounds some internal components of the compressor.
   • Perform a visual inspection to see if the sleeve has turned brown.
   • If the sleeve is brown, this indicates demagnetization or loss of magnetic properties due to high temperatures.
   • This change in color could signal that the compressor has been operating at abnormally high temperatures.