CH27
LG Inverter Module Overheating (IPM Overheat Protection)

System shows CH27 and will not operate normally.

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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

Blocked airflow around outdoor unit causing poor cooling of inverter module, Failed outdoor fan motor, Degraded thermal compound or heat sink contact on IPM, High ambient temperature combined with heavy load

How to Fix / Troubleshooting

Safety: Disconnect power before removing outdoor panels. The heat sink and power components can be very hot.

Steps:

  • Improve ventilation: Ensure the outdoor unit has adequate clearance on all sides and above. Remove covers or obstructions that trap heat.
  • Clean coil and fan: Clean the outdoor coil and fan blades to improve heat rejection.
  • Check fan operation: Verify the outdoor fan runs at appropriate speed. A slow or non-running fan can overheat the inverter.
  • Power reset: After cleaning and ensuring airflow, power off for 10 minutes, then on, and test.

Technician required: If CH27 continues, the IPM heat sink, thermal interface, or the inverter PCB itself may be failing and should be serviced or replaced by a professional.

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Repair Difficulty

Professional Required 5/5

Required Part

Outdoor Inverter PCB
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