Furnace attempts ignition but locks out after several tries; LED shows code 14 (ignition lockout). Inducer runs, ignitor glows, but burners fail to stay lit.
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
Safety first: Turn off power and gas supply before servicing. Allow furnace to cool.
- Observe ignition sequence: With panels on and power restored, call for heat and watch through the sight glass. Confirm inducer starts, ignitor glows, gas valve clicks, and burners light briefly then go out.
- Clean flame sensor: Turn power and gas OFF. Locate the flame sensor (a small metal rod with a single wire, mounted at the burner). Remove the mounting screw, gently clean the rod with fine steel wool or a Scotch-Brite pad until shiny, and reinstall. Do not touch the rod with bare fingers afterward.
- Inspect burner flame: Restore power and gas, call for heat, and check that the burner flames are blue and stable across all burners. Yellow, lifting, or uneven flames indicate dirty burners or gas issues.
- Check ignitor condition: With power OFF, visually inspect the hot surface ignitor (usually a silicon carbide or nitride element). If it is cracked, white/chalky, or damaged, it should be replaced with the correct Day & Night-compatible ignitor.
- Reset lockout: Turn power OFF for 60 seconds to clear lockout, then retry.
If the furnace still locks out with code 14, the gas valve, flame sensing circuit on the control board, or gas supply pressure may be faulty. Contact a licensed HVAC technician for gas pressure and combustion testing.