Error code reference

LG Air Conditioner Error Code 28

Master outside unit inverter DC link over-voltage error - compressor turned off due to DC voltage over-charge (over 780V).

SourceLG Air Conditioner Outside Unit - Service Manual: ARNU/URNU Seriesp. 101

LG codes LG air conditioner codes

Diagnostic procedure

The full 28 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 if input voltage is normal (R-S/S-T/T-R phase voltage 220V ±10%).

SourceLG Air Conditioner Outside Unit - Service Manual: ARNU/URNU Seriesp. 101

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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

27 manuals in the MyPros+ library document this code for LG air conditioner.

Models covered by the manuals that document this code

More models are covered than are listed here.

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The full 28 procedure

Where this code is documented

Models covered by the manuals that document this code

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