Ideal furnace locks out shortly after start, burner does not light, fan may run briefly then stop

Safety first: Turn off electrical power to the furnace at the breaker and isolate the gas supply before removing any covers. If you ever smell gas, stop immediately, ventilate the area, and contact a qualified gas engineer.

Steps:

• Reset the furnace: Turn the Ideal furnace off at the main switch for 2–3 minutes, then turn it back on and call for heat. Observe if the igniter glows and if the burner lights.
• Check the hot surface igniter: With power off, remove the burner access panel and visually inspect the igniter for cracks or white spots. If damaged or not glowing during start-up, it likely needs replacement.
• Inspect gas supply: Ensure the gas isolation valve to the furnace is fully open. If other gas appliances are also weak or not working, there may be a supply issue that requires a gas utility or engineer.
• Check wiring to gas valve and igniter: Confirm all harness plugs on the Ideal ignition control board and gas valve are fully seated and not corroded or burnt.
• Attempt one more reset: If the furnace lights briefly and then locks out again, the ignition control board or gas valve may be faulty and should be tested and replaced by a qualified technician.

Do not repeatedly reset a furnace that fails to ignite; unburned gas can accumulate and create an explosion risk.