Hot Surface Igniter Glows But No Flame? (We Have A Fix)

Eli Smith
by Eli Smith

Heating, Ventilation, and Air Conditioning (HVAC) systems have a hot surface igniter (HSI) that can occasionally stop functioning. One of the more common issues you may run into with this is having the HSI glow, but no flame appears. So what do you do when this happens?

If your hot surface igniter glows but has no flame, this could be due to your gas valve failing to open, or the igniter being too weak. This means you need to test the wires to see if your igniter needs to be replaced. Sometimes, the issue is that it needs to be cleaned.

HVAC systems can be incredibly complicated. We will get into some further details below to ensure you have ample understanding of this project. In many cases, you may wish to contact a trained professional to handle this.

Related Content: How To Tell If A Furnace Ignitor Is Bad | Water Heater Igniter Won’t Spark? | Are Furnace Gas Valves Interchangeable? | How To Light A Gas Furnace With An Electronic Ignition

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Gas Valve Not Opening On HVAC

Before starting any repair projects, be sure that you turn off the power to the furnace. You can do this from your breaker box; look for a section labeled “furnace.”

If you listen to your HVAC system, you should be able to hear the hissing of your gas valve. In some cases, your HVAC system’s flame detector may not catch a flame in time. As a result, the gas valve will fail to open.

The situation above is a safety feature, so we do not recommend trying to override this. Contact a professional HVAC installer for further details. Another common issue is related to the wires connecting the gas valve to the control panel. You can see anywhere from two to three wires in most standard HVAC systems.

You can test the wires to see if they have a current traveling through them with a voltage meter. These days, you will see incredibly small DMM probes that can be for this test with a multimeter.

If the voltage isn’t matching the standard for which the owner’s manual suggests, you likely need to replace batteries. Given HVAC systems require certifications, it will be best to contact a specialist unless you have training in the area yourself.

Igniter Too Weak On HVAC

If your furnace isn’t running, you can check out the igniter portion to see if it isn’t producing enough heat to light a flame. Your igniter may be glowing bright orange, but if it is on with the gas valve and not igniting, it is likely too weak.

Typically speaking, this is from your igniter remaining on after the gas is activated. It causes your igniter’s shelf life to reduce. It is also commonly caused by the oil from human skin being on the igniter.

Thankfully, furnace ignitors are typically very cheap, so it does not require much to replace it. There is a screw that contains the silicone igniter once you pull it out of your furnace.

You will just need to remove the old igniter by loosening a bolt or screw on the front. You can plug it into an electrical component in the furnace, so be sure you are gentle while removing it. While you do this, be sure not to touch the igniter. The oil from your fingers can cause the igniter to burn out faster.

Clean Your Furnace

The last option that can cause a lack of flames comes down to how clean your furnace is. Anything can potentially snuff out a fire, and these can include things like dust and bold insects who wish to spend time here.

When cleaning the blower, you can use a vacuum to get in-depth. You can also use a small brush, but be as detailed as possible. Leaving a little bit of dust here can cause issues down the road.

If you need to clean the igniter, blow the dust off. Don’t try and use any rags (damp or otherwise), as that could potentially ruin your igniter. Also, remember not to touch the igniter, as that will cause it to go out faster.

It is also an opportunity to clean the flame sensor, which should be clearly labeled. You can clean this with a standard cloth. A dirty flame sensor is one way your furnace fails to ignite.

How to Check and Replace the Ignitor

Call A Professional

If you have gone through all of the above steps and are still running into issues, it is time to call in the professionals. Things like replacing igniters and checking the voltage for your gas valve are pretty simple as far as HVAC issues come.

However, HVAC installers and repair professionals have to go through a litany of tests to get where they are. Because of this, you should leave any more complicated issues for someone who has training on the matter.

There are many things that you can DIY. If you want to learn, try, and see if you can’t reach out to a friend with the training. Your friend may still charge you for their time, but some people are more than happy to educate you, given the opportunity.

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Related Questions

Are Hot Surface Ignitors Interchangeable?

In many cases, there are two types of HVAC furnaces that use two standards. These are SiNi and OEM lighters. Your owner’s manual will provide the details behind this.Another critical note comes from 2012, where the first universal SiNi igniter was released. The new style SiNi igniters should replace the old style silicon carbide igniters. New SiNi igniters require a lot more detailed work, including multiple cycles.If you use an OEM igniter, this issue doesn’t come up, and is, therefore, less complicated. Technicians who saw this can sometimes be confused, so you will want to be specific with the year of the furnace.Given that most furnaces tend to be pretty old, you may not have to worry about this. Just be sure that your furnace has the right adapter and pay

What Is The Labor Cost Of Replacing A Surface Igniter?

If you decide to contact a local professional, the labor costs can be several hundred dollars. Typically speaking, it is a quick process that won’t cost more than $200.As you reach the $300 level, you may find that your furnace is pretty complicated. Therein lies the importance of shopping around.

How Long To Furnace Igniters Last?

Typically, furnace igniters can last around six years. However, this number is an average, which can reduce if you fail to clean them regularly.

What If My Furnace Is Running, But There Is No Heat?

Another standard furnace issue comes from the filters being dirty. When the filters are dirty, it can restrict the movement of heated air, which causes your house to remain cold. At this point, check to see if your blower is running. If it is, replace the filter in your furnace.

How Do Your Correct An Electronic Ignition Furnace?

In some cases, resetting your furnace may solve the ignition issue. Turn off your furnace so that it has no power of gas entering it. Please give it a couple of minutes to be sure that the gas is gone.When you turn the furnace back on, you may have to relight the pilot light manually. If this is a continuing issue, you will need to contact an HVAC professional.

Eli Smith
Eli Smith

I'm a guy who becomes the expert of whatever I stumble upon, writing-wise. I've written tons about cool home products, home improvement, and smart technology in the home. I'm also the proud father of a kiddo born on new years, making my holidays very busy.

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