H5
Pioneer IPM (Inverter Power Module) Protection / Drive Fault

Indoor unit shows H5 and system may not start or may shut down quickly

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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

Shorted IPM module, Incorrect phase output to compressor, Overheat of inverter heat sink, Faulty current sensor on inverter board

How to Fix / Troubleshooting

Safety first: The inverter section contains high voltage even after power is removed. Only qualified personnel should service the IPM.

Steps to try (user-level):

  • Power reset: Turn off the outdoor disconnect for at least 10 minutes to allow capacitors to discharge, then restore power.
  • Ensure ventilation: Confirm the outdoor unit is not enclosed or blocked, which can overheat the inverter.
  • Observe startup: Listen for abnormal noises or repeated attempts to start the compressor.

When to call a pro: H5 almost always requires a technician to test and likely replace the inverter PCB or compressor.

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Repair Difficulty

Professional Required 5/5

Required Part

Outdoor Inverter Power PCB
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