Error code reference

LG Heat Pump Error Code CH21

DC Peak (IPM Fault): instant over current in U,V,W phase or poor insulation of IPM.

SourceLG AH Series Heat Pump - Service Manualp. 61, 68

Diagnostic procedure

The full CH21 procedure

Step 1 is visible so you can confirm you are on the right page. The remaining steps, the ones that tell you whether to actually replace a part, unlock with any pass.

MyPros+ · DiagnosticsStep 1 preview

First diagnostic step

Check U,V,W wire connections; check input power voltage (1Ph: 230V±10%, 3Ph: 400V±10%); check compressor resistance and insulation; check DC link capacitor.

SourceLG AH Series Heat Pump - Service Manualp. 61, 68

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More steps, wiring diagram references, and verified part numbers

Includes expected resistance and voltage values, connector pinouts, and supersession notes for replacement parts.

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Where this code is documented

1 manual in the MyPros+ library documents this code for LG heat pump.

Models covered by the manuals that document this code

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The full CH21 procedure

Where this code is documented

Models covered by the manuals that document this code

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