H4
Sencor Inverter Module / Compressor Drive Protection

Display shows H4, unit may not start compressor.

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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

Faulty inverter power module on PCB, Shorted compressor windings, Poor grounding, Overvoltage or undervoltage supply

How to Fix / Troubleshooting

Safety first: This fault involves high-voltage inverter electronics. Only qualified personnel should service internal power components.

  • Step 1 – Check supply voltage: Ensure the supply voltage matches the rating on the Sencor nameplate and is stable.
  • Step 2 – Power reset: Turn off the breaker for 10–15 minutes to allow the inverter module to discharge, then restore power.
  • Step 3 – Visual PCB inspection: With power off, inspect the outdoor PCB for burnt components or cracked solder joints around the power module.
  • Step 4 – Professional diagnosis: If H4 persists, a technician should test compressor windings and the inverter module. Replacement of the outdoor PCB or compressor may be required.
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Repair Difficulty

Professional Required 5/5

Required Part

Outdoor Inverter Power PCB
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