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Error code reference
Lennox Air Conditioner Error Code E426
Excessive inverter alarms - after ten faults within one hour, control is locked out indicating poor system operation.
SourceLennox Air Conditioner - Service Manual: Elite Series XC20p. 32
Diagnostic procedure
The full E426 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
1
First diagnostic step
Review history of alarms. Check condenser fan motor, TXV, indoor unit blower motor, over-charge, undercharge, or clogged refrigerant filter. Disconnect power to outdoor unit and restart.
SourceLennox Air Conditioner - Service Manual: Elite Series XC20p. 32
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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