Lennox
Burners Not Igniting / No Flame
Furnace runs but produces no heat; blower runs continuously with cool air from vents.
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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.
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Possible Causes
Closed gas shutoff to Lennox furnace, Faulty hot surface ignitor, Faulty gas valve, Broken ignitor or gas valve wiring harness
How to Fix / Troubleshooting
Danger: If you smell gas, shut off gas at the main valve, evacuate, and call the gas utility.
- 1. Thermostat check: Confirm thermostat is set to HEAT and temperature is above room temperature.
- 2. Gas supply: Ensure the manual gas valve near the furnace is open and other gas appliances work.
- 3. Observe ignition: Through the sight glass, watch for the ignitor glowing when there is a call for heat. If it never glows, the ignitor or control board may be faulty.
- 4. Call a technician: Gas valve and ignition circuit testing require specialized tools and training.
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Repair Difficulty
Professional Required
5/5
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