What This Error Means

Error code 11 indicates a failed ignition attempt. After four consecutive failures, the control enters a one-hour lockout and alternates codes 11 and 10.

Symptoms You May Notice

Inducer runs but burners do not ignite; spark occurs without successful ignition; burners light briefly and shut off; repeated ignition attempts; eventual one-hour lockout.

Common Causes

Dirty or disconnected flame sensor; gas shutoff valve closed; failed or incorrectly positioned spark igniter; loose ignition wiring; improper furnace grounding; poor burner crossover; incorrect gas pressure; faulty integrated furnace control.

Safe Troubleshooting Steps

1. Confirm the thermostat is calling for heat. 2. Confirm the manual gas shutoff valve is open and the home has gas service. 3. Turn off furnace power before opening an access panel. 4. Inspect the ignition and flame-sensor wiring for obvious looseness or damage. 5. Review the Flame Sensor Troubleshooting Guide at /flame-sensor-troubleshooting/. 6. Restore power once and observe whether the burners ignite and remain lit. 7. Do not continue resetting the furnace. 8. A qualified technician should verify ignition operation, flame-sense current, grounding, gas pressure, burner crossover, and control outputs.

Parts Commonly Involved

Spark igniter; flame sensor; burners and crossover ports; gas valve; integrated furnace control; ignition wiring; grounding connections.

When to Call a Technician

Yes if ignition fails more than once, the burners will not remain lit, or the furnace enters code 10 lockout.

Safety Notice

Do not handle gas-valve components or test live ignition circuits unless qualified. Leave the area and contact the gas supplier from a safe location if you smell gas.

Manufacturer Documentation