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Olive Explains: Why Your Furnace’s Burners Aren’t Lighting

Gas Burner

Here’s an irritating problem: you set your thermostat for something comfy during winter. I recommend 68°F, even though my nice fur coat lets me set it lower than you would. It’s a cold day, so that means setting the thermostat to that temperature will cause the furnace to come on. But it doesn’t. The fan might turn on, but not warm air. When you go to the furnace, you discover that the customary blue glow from the burners isn’t there—they haven’t ignited. What’s going on?

Well, I can list a few possibilities…

Let’s go back to the thermostat for a second

The problem may not be with the furnace, but with the thermostat. It sends the signal to the furnace to light the burners and turn on the blower fan. Those are separate connections, so it might lose one of those and you’ll have the blower come on, but no signal to the burners to send gas flowing or for the igniter to light them. The thermostat might also not be sensing the correct temperature in your house, and please don’t try shoving the thermostat up higher to “fix” this—you want the thermostat fixed or replaced.

Gas valves and gas flow problems

Here’s an idea you’ve probably already thought of: the burners aren’t lighting because they aren’t getting any natural gas. You may wish to check on the gas line for the house to make sure it hasn’t been shut off. If the house is receiving gas, the gas valve in the furnace might be stuck—you might hear a clicking sound from the furnace in this case, although the flame sensor in the furnace should soon shut the gas flow off as a safety measure. Never fool around with the gas lines! This work is only for professionals.

Faulty ignition system or pilot light

Depending on the age of your furnace, it either uses a standing pilot light to ignite the burners or a type of electronic ignition system. If it uses a pilot light, check if the pilot light has been extinguished. Try to relight it, but if it won’t stay lit, shut off the furnace at the furnace switch and give us a call. A broken electronic ignition system is something you’ll also need help with: we can take care of replacing it.

Faulty flame sensor

I mentioned the flame sensor before, and if you were saying, “Wait, Olive what is that?” back then, well, now I get to explain it. The flame sensor is a safety device that detects when the burners ignite after gas begins to flow. If the gas flows but the sensor doesn’t detect flames, it will shut down gas flow to keep the house safe. But if the flame sensor is malfunctioning, it might just prevent any gas from flowing to the burners, no matter what. That’s being too good at your job! But we’re just right for ours, and that is seeing you get the best HVAC service in Maryville, TN to fix this problem.

Anyway, that’s just a sample of why you may have burners that won’t light. I could give you more, but I’d be delaying you in getting to the phone and calling us up to help you get your house comfy again!

Stay warm,