LED_1_FLASH
Lennox
Ignition Failure / No Ignition
Status LED on Lennox furnace control board flashes 1 time repeatedly; furnace will not start heating cycle.
Advertisements
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.
Advertisements
Possible Causes
No gas supply to Lennox furnace, Faulty hot surface ignitor, Misaligned or dirty flame sensor, Faulty gas valve or control board ignition circuit
How to Fix / Troubleshooting
Safety: Turn off power and gas before servicing. If you smell gas, evacuate and call the gas utility.
- 1. Confirm thermostat call: Ensure thermostat is set to HEAT and temperature is above room temperature.
- 2. Check gas shutoff: Verify the manual gas valve to the furnace is open.
- 3. Inspect ignitor and flame sensor: Access the burner compartment, visually inspect the ignitor for cracks and clean the flame sensor as described earlier.
- 4. Reset furnace: Restore power and gas, then cycle power to clear lockout and observe ignition sequence.
If the LED 1-flash code returns, professional gas and ignition diagnostics are required.
Advertisements
Repair Difficulty
Hard
4/5
Required Part
Hot Surface Ignitor
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements