4 Signs of a Faulty Furnace Ignitor


When was the last time you spent a night dressed in layers, wrapped up in a blanket? We’re not talking about a high school football game on a Saturday night.

The bane of all homeowners is the furnace that quits on a cold night (or a cold morning). If you know a bit about your furnace, you can get it up and running before frostbite sets in.

Today, we’re talking about the faulty furnace ignitor. It’s a small component with a huge job. The ignitor lights the burner, which sparks the combustion process. It’s what converts your heating fuel into heat.

Read here about 5 symptoms of a bad furnace ignitor. 

The Furnace Stops Running

When a furnace won’t run at all, check for a bad ignitor. The reason? Your furnace may shut down completely if you have an ignition problem—it’s a safety measure.

If your furnace won’t ignite or won’t turn on at all, it’s giving you a sign that you need to replace the ignitor.

Be careful about making a quick judgment though because failure to run is also caused by other problems.

Your Furnace Blows Chilly Air

Unless you’ve set your thermostat to COOL, your furnace should not blow cold air. Before going too much farther in the investigation process, make sure it’s set to AUTO and HEAT.

This is another symptom of a bad furnace ignitor. Again, the ignitor isn’t lighting the burner and you have no combustion.

Without combustion, you won’t have heat!

Does Your Furnace Short Cycle?

Now here’s a tricky sign indeed. Does your furnace turn on and go through the motions, also called cycling?

When a furnace turns on and off repeatedly HVAC professionals say it’s short-cycling. This is another safety feature and it means the furnace senses a potential safety problem. 

Short-cycling is sometimes caused by a faulty ignitor. Your HVAC technician is the best troubleshooter when your furnace goes through the motions but can’t get out of the gate.

A No Glow Ignitor

Newer furnaces light with electronic ignition rather than a pilot light. Ignitors have replaced the old pilot lights in favor of safety. If you want to find your ignitor, look in the same place where you’d normally look for a pilot light.

When the furnace kicks on, the ignitor should glow. The ignitor needs to get super-hot so that it ignites the gas/air mixture needed for combustion.

Look under the furnace for the glow! If you don’t see it, you likely have a bad ignitor.

We Can Replace Your Furnace Ignitor

If you’ve read through the signs and they point to a bad ignitor, you’ll need to take the next steps. Faulty furnace ignitors don’t heal themselves and you don’t want to sit around wearing layers all winter long.

Our team is always happy to come out and replace a furnace ignitor or make any other necessary repairs. Contact us today and we’ll schedule a service call.

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