Error code reference

Lennox Air Conditioner Error Code E427

The inverter has detected a DC peak fault condition (55A or higher), causing compressor and fan to stop (inverter code 21).

SourceLennox XC25 Series - Full Service Manual: Installation & Operationp. 32

Lennox codes Lennox air conditioner codes

Diagnostic procedure

The full E427 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 for high pressure, condenser fan failure, locked compressor rotor or overcharge. Disconnect power to outdoor unit and restart.

SourceLennox XC25 Series - Full Service Manual: Installation & Operationp. 32

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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

2 manuals in the MyPros+ library document this code for Lennox air conditioner.

Models covered by the manuals that document this code

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The full E427 procedure

Where this code is documented

Models covered by the manuals that document this code

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