Furnace locks out; LED flashes 11 times repeatedly.
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Critical safety: Rollout or repeated limit trips indicate overheating and potential CO risk. Do not repeatedly reset without finding the cause.
- Check air filter and vents: Replace dirty filters and open all supply/return vents.
- Inspect rollout switches: Locate rollout switches around the burner area. If manual reset type, press the reset button once only after confirming there is no visible damage or soot.
- Verify blower operation: Ensure the blower starts promptly and runs at full speed during heat. If it fails to start or is noisy, the motor or capacitor may need replacement.
- Inspect venting: Check for blockages or disconnected vent pipes.
Persistent 11-flash lockouts require professional inspection of the heat exchanger and combustion system.
Repair Difficulty
Required Part
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