5 Signs That Your Furnace Ignitor Is Bad

Marwa Hasan
Written by Marwa Hasan
Updated August 18, 2021
Woman and dog cuddle under blanket
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A faulty ignitor is a common reason why your furnace isn’t working—but luckily, it’s usually a quick fix from a pro

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Imagine the temperature starts to drop, you turn on your thermostat to make things a little more cozy—and nothing happens. 

The furnace ignitor is a small component with a big job. It lights the burner, which sparks the combustion process and converts the gas into heat. So if your furnace won’t turn on during a chilly night, you may have a problem with the ignitor. 

Here are a few signs that your ignitor went bad.

1. The Furnace Won’t Run

When a furnace doesn’t run at all, that could be a sign you have a bad ignitor that needs replacing.

When the ignitor glows, it generates heat. But your furnace is built with a fail-safe option to shut it off in any critical situation.

2. Your Furnace Blows Cold Air

Unless your thermostat is set to cool, your furnace should not blow cold air. 

A working ignitor is key for your heater to blow hot air. A faulty ignitor won’t produce that small spark to heat the air coming from your furnace, and your heater will blow cold outside air into your home.

3. Your Furnace Turns On and Off

Man adjusts thermostat
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Does your furnace turn on and then off repeatedly? This is called short-cycling—a safety feature that happens when the furnace senses a potential safety problem. 

When you have short cycles, the ignitor could be the culprit. The bad ignitor can't hold a charge long enough to heat the furnace air, and then it forces the system to wait at least 60 seconds before it starts again.

To save yourself from a significant furnace issue, call a technician to inspect the problem as soon as you notice it's gone on and off a few times.

4. The Electric Breaker Repeatedly Trips

If your furnace keeps tripping the circuit breaker right after it starts blowing air, this could indicate a voltage issue related to your ignitor. 

While the furnace ignitor can be a simple fix, repeatedly tripping the breaker can be dangerous for your furnace and for the electrical system in your home. Take this furnace issue seriously and be sure to leave the breaker set to “off” until the furnace problem is repaired.

This ignitor issue can be dangerous because you’re dealing with lots of electricity. If you’re in this situation, call a local furnace professional.

5. You Hear a Click, But Nothing Happens

To kick-start the furnace, your ignitor creates a spark that makes a 'click' sound. But if you hear the click and no air seems to blow, you could have a dangerous ignitor problem you’ll need to have serviced by a local pro.

What Should You Do About a Faulty Furnace Ignitor?

Don’t ignore the warning signs of a bad ignitor. Your first action should be to call a local furnace repair as soon as possible to get the issue diagnosed properly. This will help you reduce any further damage to the furnace and your safety.

An ignitor repair or replacement is often inexpensive and can save you from a more significant furnace repair that will cost more. Most ignitors have a seven-year lifespan. 

Generally, you shouldn't wait until winter is here to deal with heating issues, and you should schedule routine furnace routine checkups as needed. Call a furnace maintenance professional near you to get yours looked at before you find yourself sleeping under four blankets to stay warm.

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