What causes Lennox error SMOKE ALARM?

Smoke detected by unit sensor. External smoke alarm input triggered

How do you fix Lennox fault code SMOKE ALARM?

1. Investigate the source of the smoke alarm. 2. Address the smoke condition immediately. 3. The system may require a reset after the smoke condition is cleared.

SMOKE ALARM

Display Message - SMOKE ALARM

Lennox · PRODIGY 2.0 Unit Controller

What does SMOKE ALARM mean?

A smoke alarm has been detected through the unit's input sensors. The system may shut down or alter its operation.

Common Causes

Smoke detected by unit sensor
External smoke alarm input triggered

Repair Steps & Checklist

Click steps to track your progress.

1
Investigate the source of the smoke alarm.
2
Address the smoke condition immediately.
3
The system may require a reset after the smoke condition is cleared.

Browse all codes in this manual (56)

Verified technical data. Last updated: April 2026

Source: Lennox PRODIGY 2.0 Unit Controller

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Display Message - SMOKE ALARM

What does SMOKE ALARM mean?

Display Message - SMOKE ALARM

What does SMOKE ALARM mean?

Common Causes

Repair Steps & Checklist

Related Faults