Error code reference
Lennox Air Conditioner Error Code E426
Excessive inverter alarms
Excessive inverter alarms - after ten faults within one hour, control is locked out indicating poor system operation.
First step from the service manual
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.
The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.
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Get the full diagnostic procedure for E426.
- Step-by-step tests with expected resistance, voltage, and continuity values
- Wiring diagram references and connector pinouts from the OEM service manual
- Verified part numbers when replacement is required
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