Cleaned Hot Surface Igniter Furnace Worked for Awhile and Now It s Not Again

Dan has been in the HVAC manufacture for 23 years with experience ranging from installation and service to sales and distribution.

Hot surface ignitor

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Is Your Furnace Not Lighting?

Do yous feel it getting a bit chilly? Practice you hear the furnace running, simply you're getting only common cold air and it keeps turning on and off? And then . . .

Exactly. You lot hear nix.

Well, depending on what time it is, you may desire to get some actress blankets, but the skilful news is that yous might be able to figure this one out for yourself and even prepare the trouble pretty hands.

Diagnosing a problem with your hot surface ignitor (silicon nitride or carbide ignitor) is rather simple and replacing it is but as easy. So strap on your work boots, leave your toolbox, and let'south get this thing running. (Just kidding. Yous won't need work boots at all and probably just one tool.)

Here is what a hot surface ignitor looks similar in identify in the furnace—fairly tucked abroad and correct in front of where the gas first comes into the furnace to be lit.

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What Is a Hot Surface Ignitor?

The hot surface ignitor is a device used in about modern furnaces to ignite the gas y'all use for heat. It'south a relatively simple component that works quite like a toaster in that its heat is generated by forcing 120 volts through an exposed, resistant fabric. In this case, that textile is usually silicon carbide or silicon nitride.

Now, I used the give-and-take resistant lightly. Make no mistake, this component is very fragile. It is electrically resistant, not bear on resistant at all. When treatment this component, be very conscientious not to whack it against anything, and don't touch it with your blank hands. Even the slightest crack in the ignitor can cause it not to work, and the oils from your peel tin can cause failure also.

Various types of ignitors. Type 1 - Here is the full view of the ignitor shown to a higher place. This is one of a few types.

Diagnosing the Problem

Diagnosing a faulty hot surface ignitor is really quite simple. There are very few times where your eyes and ears will fool y'all, so odds are, if you lot watch and listen, yous'll know if your ignitor is bad.

Simply watch the furnace the next fourth dimension information technology tries to start up. At that place is a risk that if your furnace was trying to start just didn't, it may be in a lockout stage. This is a safe default on your furnace and can be overridden by shutting off the principal power to the unit of measurement, waiting approximately lx seconds, and so turning information technology back on again. At present your furnace should try to restart, so watch and listen.

As the furnace begins to practise its thing, y'all'll hear the fan come on. So, perhaps—if you have one—you'll hear the smaller inducer fan turn on. Presently thereafter, you should see your hot surface ignitor begin to glow followed past a "tick" sound. This "tick" is the gas valve opening. Finally, you should see the flames ignite.

No glowing? No fire? Your hot surface ignitor is bad. At least that will be the case most of the time.

Here is an instance of the electric connection of the ignitor. Unplug the old one, and plug in the new. Information technology's that easy.

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Whorl to Proceed

Read More From Dengarden

Replacing a Furnace Ignitor

Replacing the hot surface ignitor is simple. The key, again, is to be careful because of how fragile these can be. I don't mean to dumb it down, but you just take out a screw, remove the part, and undo the prune. That's it. The new role goes dorsum in the same way the quondam role came out, only more carefully.

I do recommend buying ii; I did this when I worked on furnaces full time. This saved me a trip more than one time, and when repairing my own, I concluded up with a spare that I know I'll use someday. These tend to become out near every 5 or half dozen years, and you never know if it might be sooner, so it's good to accept one on hand.

Some other of import point is being certain you become the proper replacement. You won't observe these at your big-box home comeback stores, so call a local wholesaler for a replacement. Be sure to phone call one that deals in your unit of measurement's brand or sister brand, and have the model number ready. Take the old role with you lot along with its mounting bracket and electrical connector. Sometimes, the only difference in the ignitors will be these two items, merely they are an important difference, and so y'all want them to exist correct, too. Yous can look this function to cost somewhere betwixt $25 and $l—nonetheless much cheaper than a service call.

A side view of the ignitor in place. See the bracket leading to the right? The tip of that spiral is the simply screw you demand to remove.

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And here is a view of the burner assembly. To the right you see the wiring and clip leading to the ignitor and on the left, the wire leading to the flame sensor.

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Furnace Repair Tips

If you see the ignitor is working similar it should, so y'all likely take a different problem. Endeavour checking a couple of these items for other like shooting fish in a barrel fixes.

• Fuse: There is a three-amp fuse on your circuit lath. Of course, if it blows, and then you likely don't have anything going on at all in the furnace.
• Flame Sensor: This is a very common problem with furnaces and, again, another easy fix. With this, your furnace will likely fire and then close down almost every bit fast.
• Thermostat: Perchance it's fourth dimension to replace your old thermostat with a newer, more accurate one. Not that your furnace shutting down has to do with accuracy, but an aged thermostat can crusade a furnace to do funny things, too.

I hope that something hither has the domicile-fires burning again.

Equally always, my aim is to assistance you, and my hope is that you'll assist others.

Need More Furnace Help?

• How to Figure Out What is Wrong With Your Furnace
  Do you know how your furnace is supposed to work? If not, how do you intend to fix it? This hub will assist you understand the proper working order of a furnace so that you can pinpoint problems and repair them or know what to tell the people who will.

This article is accurate and true to the all-time of the author's cognition. Content is for informational or entertainment purposes just and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

Questions & Answers

Question: What is the correct orientation of the ignitor shield? Does it go between the ignitor gas source, or does the ignitor get betwixt the shield and gas source?

Answer: There is no igniter shield that I am aware of outside of a grill to protect it from grease. I'm not sure what yous accept or are working on, merely nothing should be betwixt the igniter and gas supply. That could slow ignition, thus creating a build-upward of gas before ignition and that'south bad.

Question: Afterwards refueling my furnace it won't boot back on. I have turned information technology off and on a few times trying to bleed the air out. What else can I do?

Respond: I don't believe kicking the furnace off and on to bleed is the proper way to exercise then. I think it's more like haemorrhage a broken line if you ran information technology empty. I would have a professional accept care of this considering I practice know if done incorrect you tin cause damage to the unit and potentially a hazardous state of affairs.

Question: I bought a new furnace igniter but it is longer than the sometime 1; is it safety to use?

Answer: So long as information technology is mounted securely and direct in the path of the gas as information technology was and so y'all should exist fine. Is it the proper voltage? That is important.

© 2012 Dan Reed

Emily on December 08, 2019:

Then is my ignitor bad if I take to fan information technology on its 2nd calorie-free? I already cleaned the sensor off and information technology seemed to work for a while simply then it stops. I am not sure if how I am diction this makes sense but I don't want to buy the incorrect office. Odd thing is information technology seems to work sometimes after turning the switch on and off a couple of times.

Michael Langan on November 12, 2019:

with an igniter with a rut sensor, does the heat sensor serve the aforementioned purpose every bit a flame sensor? I tin't find a flame sensor on my unit of measurement, notwithstanding it is behaving like a flame sensor event exists.

Brian on October 12, 2019:

And then my ignitor is turning red but the gas won't open up and catch fire. The LED diagnostic says "improper main basis or line voltage below 75 volts. Or broken ignitor, or open up ignitor circuit." Should I supercede the ignitor?

Dan Reed (writer) on Feb 26, 2018:

Be sure the igniter you're using is the proper voltage...typically 120V or 80V and also that the power being supplied by the board is proper. If not, it could be causing the problem.

Richard Thousand Cortellini on Feb 25, 2018:

since replacing the last ignitor 2.5 years ago, I've replace the ignitor 2x in the terminal 2 weeks.

Dan Reed (author) on December thirty, 2017:

kalifornia - I'm leaning towards the high limit/fan switch or ane of the roll out switches. It's certain interim like a flame sensor just with that ruled out these would be my suspects. They are rather inexpensive parts. I hope information technology is as those are easy fixes only still hard for me to be sure from hither. The video was very helpful though at that place is no real fashion to be sure without running electrical tests which it sounds similar you're capable of doing so endeavour testing those components. All-time of luck and Happy New year's day!

kailfornia on December 26, 2017:

furnace (rheem criterionII ~ 1999) shuts off after 7 seconds.

one. replaced control board

2. replaced flame sensor and checked with microamps / its working.

3. checked connections, all seem practiced.

stumped on where to go for troubleshooting from this point.

video of issue hither:

https://youtu.be/KLWK2VCf0ak

any help very appreciated. thanks!

Scott on February 10, 2017:

My igniter went out.

Checked information technology and had a modest interruption in It.

Took a very thin piece of copper capsule I had left over from trimming woods joist outside.

Gently wedged it in crack on ignitor.

Turned on furnace and the copper actually vaporized into a carbon like sunstance.

Wah lah

Ignitor lit and has worked for days.

Long plenty for me to become a replacement.

Dan Reed (writer) on December 21, 2016:

Information technology sounds as if it's maybe a force per unit area switch which would be the cheapest easiest place to kickoff.

George Wetherby on December 18, 2016:

I have a Tran XE78 gas hot air furnace. The unit of measurement runs well-nigh a full wheel but the flame turns off the inducer slows down , so information technology speeds up, the flame turns on over again and the cycle continues for approx. 3-5 minutes then turns off? Any ideas?

Dan Reed (writer) on July 30, 2012:

Thank you kindly vespawoolf. I realize how exciting HVAC is to read nearly so I practice attempt to sprinkle it with a bit of sense of humor to help ease the pain. LOL! I practice hope that should yous e'er need it, this will come up in handy.

Vespa Woolf from Peru, South America on July 30, 2012:

Normally I wouldn't read a hub about repairing a furnace, but your writing fabricated it enjoyable! I'm sure this is very helpful information for a DIYer with a broken furnace. Voted upwardly!

Marcy Goodfleisch from Planet World on July 28, 2012:

I'chiliad afraid I had to vote 'no' on this 1 - I think my rubber and the condom of maybe my entire neighborhood might hinge on that choice. I didn't know this part of the furnace existed! Every bit e'er, I learn so much from your hubs! Voted upward and up!

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Source: https://dengarden.com/appliances/How-to-Repair-the-Hot-Surface-Ignitor-in-Your-Gas-Furnace

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