Furnace Cycling On and Off - Flame Sensor Cleaning - Furnace Troubleshooting 

I used a $20 bill so the furnace knew I was a heavy hitter and not to give me any more trouble. I didn't even remove the part to clean it... just reached in, rubbed it with the 20, and BINGO, worked like a charm! Thank you!!! The internet, you just gotta love this invention!

You literally saved my families life at 4am in the morning where it's freaking freezing here in Canada. I am the handy women of this house and this did the trick. Thank you so so much! Glad I came across this specific video. Wasn't so hard to take off the screw and cleaned it with a piece of paper as I didn't have a bill. Thank-you so so much! It's nice and toasty now.

wow 9 years old and its still helping people, just helped me thank you very much

was so stressed because my newborn was living in a cold house, but this finally made my home warm just in time for winter thank u sir.

I've looked up many online articles, none of them point out the issue so concisely and accurately. You just taught me to get my heater working in 5 minutes. Amazing, thank you.

Dude, you saved my life (from my wife!). She told me at 11pm the heater was blowing cold then shut off. I climbed up in the attic, looked at what it was doing, found your video on my phone, and had the heat back on by midnight. You rock! Thanks!

We had a furnace technician our years ago, because I had no clue why my furnace wouldn’t work. He fixed it, of course, but was kind enough to teach me what you showed in this video. I find that I must do this once every fall or early winter. Definitely the sort of thing every home owner should know.

Coming here 10 years later to say that you helped us so so much! Saved us an after-hours furnace call and expense. Thank you thank you!!

My furnace was doing the same. I did as you instructed. Furnace is operating well again. Thank you.

After one whole day of trouble shooting, replacing the Hot Start Ignitor which I broke when cleaning (watch out, they ARE brittle) and giving the flame sensor a clean, in position, I eventually came across your instructions and decided to pull the flame sensor out, give it a clean and refit it. Didn't immediately fix the problem but the flame did burn a little longer before it went out. Loosened it off again, some minor repositioning, and hey presto my furnace is up and running again! Thanks for your great, and informative video!

Just followed these instructions this weekend and it worked like a charm! Thank you so much for this video. Our furnace didn't look totally like that but seeing where the flame sensor was in the video and what it looked like when you pulled it out, I was able to determine where it was. Used a fresh dollar bill and it's been great since! Saved hundreds on the heating guys coming out! Thank you!

I know you've received countless accolades for this video but I just wanted to add mine to the pile. This was a simple yet effective fix. Thank you so much for sharing this informative video. It is very much appreciated.

We believe, we believe!! At first, we doubted it was the flame sensor. But after cleaning it with a new $1 bill, the furnace turned on AND STAYED ON. Oh my gosh, we did a happy dance right next to the furnace. Bless you FIX IT Home Improvement!! You guys are awesome!!

Great video. Although I used a $10, it appears to have fixed my furnace issues :). Now I can live in a warm home again. Will definitely check out the podcast and book. Thanks again!

I watched this video, and fixed my own furnace! Thanks so much! You saved me approximately $200! I had called a hvac repair service, but they were so expensive that I decided to look up a video. So grateful for this! My sensor is on a Goodman furnace and so it was to the left, and about 6 inches back, but it connected into the valves so I could see it hanging down where the flames would be. New ten dollar bills work well too! ;) Very grateful to you! Now I can add "master furnace repair tech" to my long list of pseudo-accomplishments!

Thanks for this. Had to use this at 1am this morning. It sure seems to have done the trick. At least no issues since then. This was beyond helpful.

This was extremely useful. Our furnace was short cycling in -15 F temps. We cleaned the flame sensor and now the furnace is up and running. Thank you saving us from freezing in our home!

Furnace decided to stop on a cold Chicago December night. I figured the flame sensor was the problem; but I had no idea it could be fixed this easily. Thanks a lot - you saved me a ton of $$s.

THANK YOU so much for posting this video! 3:30 a.m. and my wife and baby will hopefully stay asleep and not notice that it's 50 degrees right now. What a simple fix, clearly explained and displayed. What a lifesaver! Thank you!!

I used a $20 bill too. It was the only bill I had at the time but that doesn't matter, what matters most is this worked. Thank you very much for taking the time to make this video, you helped keep my family warm again, and that is worth more than any bill used to clean the flame sensor.

Thanks so much for this video! This was exactly the problem. I used an older one dollar bill, but didn't have much success. I switched to a crisp five and it worked perfectly! A huge help! Thanks again!

THANK YOU! 4am furnace won't stay on with wind chill -7 outside house is freezing cold. found your video 10 mins and $1 Bill later and it's now been on longer than it has in the last 4 days.

Thank you so much! I think you literally may have saved my life! I awoke in the middle of a -30 degree Saskatchewan winter night to a very cold house and my furnace doing exactly this. A google search led me to your video and I followed your instructions. Now I can go back to bed and not freeze, yay!!

I want to express my appreciation for your time in sharing your knowledge. It's January and cold in the Northwest. I cleaned the sensor the way you outlined and my furnace is back on. Thank You!

LOL. Adds a whole new meaning to a "5 dollar fix"

Thanks for the video. We'd been calling for repairs for this issue about once every two years. This was a "bad" year and I just did this myself and it's heating fine now. Saved me a bit of cash (especially for a New Years Eve call) with a five minute fix.

I used a $20 dollar bill and it totally solved the problem man you are a genius.. Thank you!

Thank you! Furnace issues on Christmas Eve in Northern Indiana. No experience with furnaces. I cleaned the sensors and it kicked back on. Christmas miracle!

Thanks a lot, you are a lifesaver! My burner was igniting and turning off after 10 seconds. I was wondering why the house felt so darn cold. Did exactly as you instructed on a Concord 80 and problem solved! Awesome informative video. Thanks so much!

I love youtube, I appreciate ppl like you posting helpful stuff, thanks a lot, it worked like a charm :)

I had to do this at 4AM on Thanksgiving day! You saved my family's Thanksgiving not to mention saving me a lot of money! I can't thank you enough!!!

This video saved my husband and I hassle (and money) tonight. Just a simple google search with this issue and your video popped up. Thank you for bring so concise and helpful.

A pretty good video. Amazingly, I actually learned something I didn't know about furnaces. In the past, I've had to diagnose and repair furnaces without internet help. On the other hand, I'm quite certain that cleaning that thing will bring mine to life...I'm pretty sure mine has a piezo igniter. The house before this one had an ancient ('70s) furnace with a glow bar. Well, anything learned is valuable, and while I have the cover off, I'll clean that sensor...my extra fine sandpaper just happens to be only a few feet from the furnace. How convenient!

How much longer will the flame sensor last if I used a $100 bill to clean it?

Having had a HVAC specialist come out at least x2 before for the same issue and paying north of $150 for the callout fee and replacement sensor parts I'm immensely grateful for this thorough explanation and the instructions -- i followed them and fixed my HVAC in less than 10 minutes. Thank you!

Great video - short and to the point. I have a Lennox furnace with a similar sensor setup and this video and your commentary helped to quickly resolve my issue within minutes. I struggled for a minute trying to pull the sensor out since it was L-shaped, but once I did, I cleaned it off with my handy dandy dollar bill and I was back in business with heat. Thank You.

FYI...I had a very similar situation where the furnace was cycling on and off, but as the cold air came on to cool the system it would remain in this state thus cooling the house and undoing all the heat. I did the above mentioned method and it didn't fix the issue however the flame sensor did need a cleaning. So I started doing some thinking and remembered that when it came time to change the filter I decided to change brands and put in one of the best filters on the market. After realizing this, I experimented by taking the filter out and running the system without it. That solved the problem and my unit started working properly. So what I did was buy a thinner more basic filter and the system works awesome now. The top tier filters were to thick and decreased air flow. When summer comes back around this will probably improve the cooling as well for I noticed it wasn't working properly. Hope this helps some of you.

Thanks! Wasn't the issue with mine this time, but good to know it is easy to check and clean. My issue happened to be water buildup blocking the exhaust pipe. I shop vacuumed out a litre of water and everything was good after that. Need to talk to the installers about fixing the root cause

Thank you so much. I am between jobs right now and didn't have the money for a HVAC guy. Thank you for helping keeping my family warm!

Furnace did this on Sunday morning. Flat broke and couldn't afford even a cup of coffee at the time. Saw this video and followed instructions and thank you Jesus it worked. Thank you sir for providing my small miracle when I really needed it.

worked like a charm! Even on a unit that wasn't a carrier, I was able to find the sensor, clean it, and get it going. Praise the Lord for you and your help

Just fixed it with your advice at the end of 2019!! It worked!!

Big thanks for this video. Furnace was cycling and it was Christmas Eve and 7 degrees F outside. This video saved christmas.

Somerset, NJ, snowing today, came home at 55F temp inside the house. This video saved my day and made me a hero, not to mention avoiding calling a furnace guy and paying big bucks. Thanks!!!!

Do you itemize that five dollar bill on the invoice and if so, what is the standard mark-up on it?

Must be making good $ to use five dollar bills to clean parts!. Thank for the tip. I think this is the remedy for my furnace.

Decided to look up possible reasons for my apartment being so cold before I called the maintenance guy and this instantly worked. Bless you!

Tried this tonight (still pertinent info 6 years later) and it seemed to work right off the bat. Thank you sir!

Can't thank you enough for this video! Now I feel like a bad ass haha

I was trying to fix my heater too, unfortunately I don't have a clean $5 bill handy. LOL!

Christmas morning no heat!!! Your advice saved me $400.00..using a dollar bill and a flathead screw driver!!!!! Much love and appreciation for this info!!!

Been beating up the old Honeywell thermostat and getting it to randomly trigger the heating but it not having any correlation between temperature and setting. Living in Alaska, its been in the minus 5-10c and the heating was getting way too hot and then started not firing at all. Badly maintained system so changed the intake filter and made things worse. Every article said the thermostat would be at fault. Then I got lucky and came across this and one other YT video that showed me how to clean the sensor. Cleaned mine with a new kitchen green pad. Currently sitting in a house that's getting warmer and planning to dine off how much money I saved for years. Many, many thanks. nearly a decade later and you're still a legend for posting this.

You're a Gentleman and a Baller, and in addition to that you've found good use for the Fed's clown money.

hes using a 5 dollar bill... baller status

I used a $20. It worked. Happy family. I feel like I should mail the $20 to you! thanks for clear video help. You restored my faith in the internet.

woke up this morning to a cold house, furnace was doing the same thing, found this video and it worked like a charm! Thanks!

I wonder how many people just purchased a new furnace instead

Heck , I'd use $100 bill if I could borrow one ! 😄

I've had this problem intermittently for the last 2 years. Finally Googled it and your video came up. My Ducane furnace was a little more complicated to get to the part but I was able to get it done within an hour. Listening to it hum like a champ now. Thanks a lot!

Thank you!!! You saved us. I even had a furnace repair guy come and he replaced the thermostat, charged me $400 and left. Then it was warm for a few weeks but the furnace still seemed to lag. Tonight it’s 5 deg F and the house was down in the lower 60s. I found your video after watching the furnace try to light and fail, cleaned the sensor, and now have a warm house. Thank you very much!

If I had five bucks I could fix my furnace.

Thanks so very, very much FIX IT!!!! Woke up at 3am to a cold house and a furnace making a cycling noise. I found your awesome video and cleaned the flame sensor. Your video showing the exact symptoms I saw in my furnace gave me the confidence to try the solution myself and now the unit is pumping out hot air. So glad I am not freezing and even more glad that I don't have to call an HVAC company in the morning. You rock!!!

Came home today to my 2017 furnace short cycling. I'm an electrician so I know all the power points to check, but to no evail. Everything was fine electrically speaking. Almost called a 24/7 Hvac company but decided to check the ole' interwebs first. Stumbled across your video and come to find out, my issue was exactly what you covered. Cleaned the flame sensor exactly as you described and voila, fixed!! Thanks dude! Subscribed!

Thank you so so much for this. You saved me not only a couple hundred dollars for a visit from an HVAC company- but you also saved my family from a couple of very cold nights. I wish I could send you something in return!!! I appreciate this so much, thank you sincerely

Thank you so much! I used a piece of white paper to clean the sensor & now my furnace is running like a charm. You saved me like $90 on a house call. I spoke to so many people all wanting money just to come look at this furnace just so that they could come here & clean the tiny piece that was causing so many issues.

You are the best! I'm getting ready to buy my first home so I started looking for home improvement podcasts and found your show about a week ago. I love it! Great tips and awesome advise! You guys are great! Keep it up!

Thanks so much. I just cleaned my sensor after watching your video and it worked again. Don't have to call a technician to fix it. Save me lots of money.

Thank you for sharing how to fix the on and off cycle. We have a house full of people and you saved us this winter !!!

You are a lifesaver, I had just paid to have a guy come out and fix our furnace, but it happened to be working while he was here… and promptly went back to blowing cold air when he left. I climbed up and did this and now it’s perfect!!!

Amazing! My 1 year old furnace quit working and I was panicking as it’s 30° here right now outside. Watched this video and it fixed my issue. Saved me $$ not having to call an hvac company. Thank you!!!!!!!!!!!!

I just watched your video and fixed the furnace after the Landlord couldn't. I read the codes which indicated a dirty sensor and found this video. Not only did it work m but it saved my DISABLED, 65 YO Mom from having to turn it on all night so she wouldnt freeze while I was at work. THANK YOU SO MUCH!

Thank you! I kept waking up to a chilly house. Was going to call the HVAC guy, but watched your video. Watched my furnace do its heating cycle and saw the same behavior so I abraded the sensor material with a $2 bill (lol) and sanded the spade connector for good measure as it looked a bit grungy. Reassembled, and now the furnace stays running and my house is warm again :) Thanks so much!

Another fix here. Thanks! Did the trick. 6 years old video, still saving lives!

Just like the other viewers, thank you so much for this video! After I pulled my flame sensor off it didn't look like yours in the video, not blackened. It did seem to have a slight discoloration, so I said what the heck I'll try it and used emery cloth. Cleaned it up really good, put it back in and positioned it the way it was, turned it on and the burner made it past the cycling off it had been doing and blower kicked on and FIXED!!!! THANKS AGAIN!

Thanks a million!!! I just fixed my furnace at 4:30 in the morning, after realizing the burners weren't staying lit!! Thanks so much for the video!

Three minute video saved me 3 hours on the phone and a $300 service call. Thank you for taking the time to explain this.

My house hasn't been above 58 degrees in a few years. Thid video was such a blessing for our family. All I could find in the house was a nail file and it worked. Thanks so much

I can't thank you enough. I can repair an anthracite coal furnace blind folded, but had no idea what to do with a propane furnace and am recovering from meningitis. You explained it so clearly that I was able to fix it easily. Thank you so much and I hope you have a very Merry Christmas.

Your vid just saved me a late night call to a repair man on a well below freezing night. A few screws, a $1 bill and everything is back in order. Thank you.

My furnace was doing this, googled possible issue and came across this video. I used a fine grit drywall sanding sponge and wiped sensor down after cleaning, furnace fired right up and I end up looking like a hero to the wife and feel immensely proud of not calling the $90.00 per hour HVAC company. This may be the best, easiest to follow and comprehensive video for a DIY repair of any sort I’ve ever seen. Thanks.

An actual honest repair guy showed me how to do this last year and I forgot which wire it was! So, thanks for this!

You just saved me a service call! I cleaned off the sensor with a crisp $20 bill and showed my son a few handyman things at the same time. Good video!

It's 5 am Sunday morning on our daughters birthday and the furnace decides to give us troubles. Thank you this help was a real saver! We have absolutely no extra money right now to have a tech come and your tips worked like a charm. Thank you Thank you Thank you!!!!!!!

amazing! This solution was incredibly useful. I canceled my appointment with the technician! solve my problem and my family will sleep warmly in chicago thanks to this video! can save lives! THANKYOU SO MUCH

We just got home from Christmas vacation to a really chilly home and this video helped warm us up again. Thanks!

An old video but it really helped me out. When you said 90% of the time this is the issue I was really excited to know that someone like me without any hvac knowledge could get my heat back on. Sure enough it worked. Thanks a lot.

Great tip, thank you! Roughly 6 yrs later and still significantly effective! Thx for sharing.

Excellent. Concise and accurate. My gas furnace flashes a code to direct you to the possible problem. (short blinks followed by long blinks of the red light on the circuit board correspond to numbers on a trouble shooting chart) With a little courage and great videos like this, the average DIY homeowner can save lots of time and money. I saved an additional $4 by using a new one dollar bill instead of the five.

Wow this was exactly what I needed! This worked perfectly - just used an abrasive dish rag that was already in my laundry room, and it stopped the cycling immediately! You are amazing!

Your video is awesome and gave me the courage to fix my furnace problem! I suspected it was a dirty flame sensor and, sure enough, I cleaned it and now my heat works. You saved me a lot of money! It's a cold night too, so thank you very much!!!

I wish I can give you more than 1 LIKE. You saved me a few hundred bucks. 24Jan19, I woke up to a cold house. When I came across your video, I followed your steps and my heater was up and running again. However, I did not use money to clean the flame sensor rod, I used a Emery cloth. Again thank you for sharing.

My furnace was doing this exact thing. Followed your video and it came right on without hesitation. Thank you so much.

Heat out on the night before Thanksgiving. Thank you very much for this FIY tip - saved me what would likely have been an expensive holiday rate service visit. Your video is GREATLY appreciated!

thank you so much- I am not a furnace repair guy, but used this video to fix our furnace. THANK YOU

This fixed my furnace!!! It is a Rheem which was a pain in the butt, the sensor is located under the burner and back about 4 inches. Thank you so much!! It's about 33 F today and the house hasn't gotten above 55 in a day or more...65 degrees and counting ever since the fix the burners been on non-stop to catch back up! Thank you thank you thank you

Wow...thanks for the video. Got home at 1am after being out for New Year's Eve and upstairs furnace was cycling off as soon as it lit. 15 mins later, based on your instruction, back up and running. Supposed to get down near 0 degrees F tonight...would have been a little rough without your help!

I'm a MN mom stuck in a snowstorm. This saved us from freezing tonight!! My two children thank you.

My pregnant wife (who has never held a screwdriver in her life) managed to fix ours thanks to this video. I would’ve done it, but it started to act up as I was leaving for work. She wasn’t about to sit in a cold house (MI winter) thank you so much!! Still having HVAC come to perform maintenance, but at least it’s running until they arrive

This video literally just saved me $300- which post Christmas is huge! Thanks!!!!!

Idc but you just saved my life i literally just did this n it worked and i have 4 small children and its like 9 degrees here in illinois right now so grateful of this thank you