P1
Hitachi
Voltage Protection / Power Supply Abnormality
Unit stops with P1, may be related to power supply issues
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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
Low or high supply voltage, Loose power terminals, Undersized wiring or breaker, Faulty power supply section on PCB
How to Fix / Troubleshooting
Safety first: Power circuits can be lethal. If you are not experienced, limit yourself to basic checks.
Steps:
- Check breaker and wiring: Ensure the AC is on a dedicated circuit with correct breaker size and wire gauge as per Hitachi installation manual.
- Measure voltage (qualified only): Verify that supply voltage is within the specified range. Persistent low/high voltage requires an electrician or utility intervention.
- Inspect terminals: With power OFF, tighten all terminal screws at indoor and outdoor units.
If P1 persists with correct voltage: The internal power supply on the PCB may be defective and require replacement.
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Repair Difficulty
Hard
4/5
Required Part
Power Supply Section of Main PCB
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