Lennox Error Codes

Select an error code below to identify the problem and find the solution.

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Disclaimer: This information is for general reference. Error codes can vary by model and production year. Always refer to your machine's specific manual and the information printed on the unit itself.

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16 published codes

List all error code index

Off / Off

Lennox Off / Off

No power at the control board, causing complete system inactivity.

Slow Flash / Slow Flash

Lennox Slow Flash / Slow Flash

Blower motor fault or normal operation depending on system model.

Alt Slow Flash / Alt Slow Flash

Lennox Alt Slow Flash / Alt Slow Flash

Flame failure or watchguard mode due to repeated ignition or flame loss.

On / Slow Flash

Lennox On / Slow Flash

Primary limit or rollout switch open due to furnace overheating.

Slow Flash / On

Lennox Slow Flash / On

Auxiliary safety circuit (secondary limit or flame rollout) switch is open.

Slow Flash / Fast Flash

Lennox Slow Flash / Fast Flash

Low flame signal detected due to weak flame sensor current.

Fast Flash / Slow Flash

Lennox Fast Flash / Slow Flash

Reversed line polarity or improper ground fault causing system lockout.

Alt Fast Flash / Alt Fast Flash

Lennox Alt Fast Flash / Alt Fast Flash

Control board failure or out-of-range voltage issue.

E200

Lennox E200

Hard lockout triggered by an open flame rollout switch.

E201

Lennox E201

Loss of communication between control board and indoor blower motor.

E202

Lennox E202

Loss of communication between control board and outdoor unit.

E223

Lennox E223

Low pressure switch is open during cooling or heat pump operation.

E225

Lennox E225

High pressure switch is open during cooling or heat pump operation.

E241

Lennox E241

Flame sensor out of sequence with flame detected while gas valve is off.

E292

Lennox E292

Indoor blower motor failed to start.

E312

Lennox E312

Blower running at reduced speed due to low airflow condition.

Code Index

All Codes

Alt Fast Flash / Alt Fast Flash Alt Slow Flash / Alt Slow Flash E200 E201 E202 E223 E225 E241 E292 E312 Fast Flash / Slow Flash Off / Off On / Slow Flash Slow Flash / Fast Flash Slow Flash / On Slow Flash / Slow Flash

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