LED flashes code 14; furnace locks out after failed ignition attempts, may retry after an hour.

Safety: Turn off power and gas before removing burner or ignition components. Do not repeatedly reset a furnace that fails to ignite; unburned gas can accumulate.

Steps:

• Verify gas supply: Ensure the manual gas shutoff valve near the furnace is parallel to the pipe (open). Confirm gas service to the home is active.
• Observe ignition sequence: With the blower door in place and power on, call for heat and watch through the sight glass: inducer starts → ignitor glows → gas valve clicks → burners light. Note at which step it fails.
• Inspect hot surface ignitor: Turn off power and gas. Remove the ignitor (typically mounted on the burner assembly). Check for cracks or white chalky buildup. Do not touch the element with bare fingers.
• Test ignitor resistance: Using a multimeter, measure resistance across the ignitor leads. Typical Comfortmaker silicon nitride ignitors read 40–200 ohms. Infinite or zero ohms indicates failure.
• Clean flame sensor: Remove the flame sensor rod (usually a single rod near the burner). Gently clean with fine steel wool or emery cloth until shiny. Reinstall firmly.
• Check gas valve wiring: Inspect the harness from the control board (e.g., HK42FZ series) to the gas valve for loose or damaged wires.

When to call a technician: If the ignitor tests good but there is no gas flow, or if the gas valve is suspected faulty, a licensed technician should test gas pressures and replace the valve if needed.