Great video, my furnace just went down and the temperature inside the house was dropping. Thanks to this video I fixed the problem in no less than 5min.
Thank you, I’m in Canada w -39 temp rite now. & my furnace broke, thank goodness I found the person who installed it,coming in the morning,it’s less than 5 years old, just bought the house. Pretty scary that’s for sure. Take care thanks for sharing.
Very noble of you to help those upcoming techs who can't afford trade school, or work for a company who won't afford the expense of getting their labor pool properly trained. I'll look forward to more of your vids. I'm an old DIY type on a limited income who need these informative vids, so thank you, thank you!!!
In the last couple of hours I watched my HVAC technician use sandpaper on my flame sensor, I will not let it happen again after watching your video. He also tried to tell me I needed it replaced & I asked why it couldn’t be cleaned. Thank you
Yikes! If he cleaned it with sandpaper it’s probably not a bad idea to replace it at some point now. Coarse abrasives will leave grooves in the sensor that collect carbon buildup more quickly. Not saying you need to rush and order a new sensor today, but find the right one and have it ready for an easy swap next fall. They’re really not expensive to get, and it gives you a little peace of mind!
My Lennox furnace would start and run for a bit and shut down. After cleaning the flame sensor , the same run and stop would happen. I then put in a brand new flame sensor and again the same condition of run for awhile and shut down. The path to ground ( in the flame) is to the front of the burner at the flame sensor. When I cleaned the face of the burner with fine sandpaper this fixed the problem and the furnace has been operating correctly. It is just like a battery with dirty connection, it is better to clean both terminals.
Perfect! The path to ground was interrupted, just like we described in the video! Cleaning the burners is part of every manufacturers recommended annual maintenance. Great analogy regarding the battery terminals, I'm stealing that one!
Flame senses don't work like that The flame sensor cathode rod is heated by the flame which excites the molecules inside creating the electrical field that goes through the cable back to the circuit board to tell it that it's on there is no path to ground unless you're talking about a spark ignition with the ground being the casing in that case yes
Thank you!!!! Explains why we are so cold in our new house. Very educational and helpful video. Saw another video (first that google showed and yours was below it on YT) and the guy gave crap info. Hubby was injured in a motorcycle accident and can’t climb to the attic. He has an “HVAC card” so was telling me about the “inner workings”. So seeing this helped me understand what to do since I have to climb into the attic to do it myself, lol. Thank you!!!! Hoping it fixes our issue.
This was the exact problem that I had. Removed the flame sensor, cleaned it off with a Scotch Brite Sponge pad, re-installed it and the furnace works great. Thanks for the great explanation, saving me a service call, and getting my heater back working in short order.
I'm so glad this worked for you! I run across this issue so often! I was really hoping it would save somebody a trip charge and diagnostic fee for such a simple fix! Keep in mind that there are dozens of other things that a qualified technician should be checking and cleaning annually, during a much less expensive maintenance visit!
I was surprised at the lack of information online regarding how flame rectification works (and a lot of misinformation), so I figured that it may be a good resource for others in the future!
This video was super helpful! The burner/flame was turning on for five seconds then turning off, then a minute later, the same thing, repeat. This fixed the issue. Thank you so much for making this video!
You have no idea how good this made me feel! I'm so glad that my video was able to help you! Don't hesitate to ask me any HVAC related questions you may have in the future!
It’s 12am here in Chicago on Christmas Day and currently -3 degrees outside. This started happening about 10 hours ago with my Amana Distinctions unit; this fix cleared it right up after about 20 minutes of work. Thank you so much for this!
I really appreciate your video especially the explaining about it all at the end. I'm definitely not a service person. Just a home owner looking for help. Good luck and Happy Holidays to your Family and you Sir ..👍🏼👌🏼🙏🏽🙂
Well explained 👏 I didn't have any thing to clean it with but was mentioned elsewhere about using a dollar bill which worked for me. Thanks again 👍🏼👌🏼🙂
I remember about 25 years ago when I was in school for this I had an old-timer instructor that told us the dollar bill trick because it was not harsh enough to destroy it but it was enough to get the carbons set build up I've used it many times if I didn't have something to clean it with
Very good. I had this exact problem. I took out the flame sensor (1/4" bolts) cleaned it with Scotch Brite and put it back. Turned on the power, blower went on, ignitor went on, flame went on, but after 2 seconds cut out again just like before I cleaned the FS. I left it running and after a minute, ignitor went on, flame went on and sustained. I guess on the first try some residual current was left in the circuit.
Perhaps also some processor checks. Engineers place coding loops to check if fault automatically clears. Some products may have to be restarted ie, pull the plug and reinsert.
Wow your explanation is excellent especially about how the electricity flows through the flame to ground. Never have I heard this explained. Now I understand the two important points that allow the furnace to operate safely and when and why it will shut itself down to protect life. Subscribed happily to your channel and thanks!
Appreciate the video. Followed most of the steps outlined in the video but unfortunately, the screw holding the sensor in place was in such an awkward spot that I didn't have the ability to take it out. I was however, able to look at the sensor after taking off the cover for the burner and I could see a lot of buildup on the sensor. If only it had been made more accessible I could have at least cleaned it until I could have it replaced during my annual servicing.
It might get you through the night or a few days! But preferably it should be removed and fully cleaned. You may need to get an angled offset tool or just use an open ended wrench to get the screw out.
Did it work? I'm not sure what furnace you have or what 8 flashes indicates on the board. There should be a label inside the door of the furnace that tells you what all of the different codes mean.
I like how you show the symbols on the multimeter. I get screwed up with those all the time. The only one I know is the “OMEGA - horse shoe” symbol means “amps”.
Yes, the control board is sending 3microamps into the flame sensor. But doesn't the control board needs to confirm some microamps going back to the board? Nice video. Thanks
The circuit board is sending a potential of much more than 3µA into the sensor. However, only some of that amperage can make it through the flame and back to ground, completing the circuit. The circuit board measures the flow of electrons, that actually make it through the flame.
In most cases the heating cycle will not end until the thermostat is satisfied. If there is a large discrepancy between the current indoor temperature and the thermostat setting it could takes hours, if it's just a degree or two it could be only minutes. Some modern thermostats have something called a "cycle rate" built into their program, and an algorithm within the stat strive to balance the furnace's run time around that rate, normally this is 3-5 cycles per hour for a forced air furnace, but there are way too many brands and settings to say for sure what yours is.
@@FixMyHeatHVAC I just googled ingredients. Some removers have additives. While working in hospital maintenance, carpenter would always use acetone for cleaning. RN's unglued my super-glued fingers numerous times! Of course, you don't want to wet skin with pure acetone. A small container with a swab would probably work best.
@@FixMyHeatHVAC A spray can of carburetor cleaner would be another option. What about electrical contact spray cleaner? I think this would be a good option. The bio-med techs used it all the time for cleaning contacts and controls.
I recently cleaned my flame sensor with 180 grit emery cloth. Probably a bad idea. I'm having trouble finding a new flame sensor for my Bryant furnace as all replacement flame sensors have the metal mounting ring in the wrong "clock" position as upon install, the sensor isn't even in the flame. Now I've probably shortened the life of my original 21 year old sensor with the emery cloth. I found very fine steel wool to not clean well enough to keep the sensor lasting very long although I'm on natural gas. I'll definitely remember the bronze brush technique.
At least it was a fairly high grit of sandpaper. The grooves in the sensor that the sandpaper leaves may cause the sensor to become dirtier faster, but it didn't instantly ruin your sensor. Measuring a before and after of the flame signal when cleaning will tell you if there was detrimental damage done. Otherwise, if you can't find the part online, try to find your closest Bryant (Carrier, Day & Night, Payne) Dealer and have them order you one.
I just had my yearly inspection and the service tech. said my flame sensor was reading higher than normal. 7 or something like that. I think he said around 3 was normal. I am wondering why he didn't clean it after watching this video and seeing how easy that would have been for him to do. They said it would cost another service call of $199.00 + the part to fix it when it goes out. Can you tell me if cleaning a flame sensor is part of yearly maintenance? I have not had any problems with the unit yet, it is only on it's 2nd winter here in Oklahoma where it's not really cold like up north.
I can't be sure, but I am fairly positive that they were referring to the hot surface ignitor when stating that it was "reading higher than normal." Measuring the resistance through that device can help give an indication of its working condition and livelihood. It is very uncommon to have to replace a flame sensor. I always clean the flame sensor during annual maintenance. 85% (estimated) of my service calls for no heat are caused by lack of proper maintenance. I also have another video covering hot surface ignitors here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-CR_xKq-uKSY.html In that video I cover the identification, diagnosis, and replacement of one particular HSI, but yours may be different.
I have to clean my flame sensor very often which I don't think is normal. Do you think its because I'm not cleaning it well enough or is there something else I should check or clean. Repairmen tell me my furnace is working fine, but then why am I cleaning the flame center 3 or 4 times a week? When its very cold out, is when my furnace does this because it is constantly running. I set it at 72 degrees and the furnace kicks on and runs then shuts off for like 5 minutes then it has to kick on again. I have a Thermo Pride Furnace and it is also my central air in the summer. I live in a mobile home in MN. and I have very poor insulation and so that is why it is constantly kicking on, on very cold days/nights. Thank you in advance for any tips or advice you maybe able to give me. Happy Holidays to all.
You could always replace the flame sensor to see if this solves your issue. They are normally relatively cheap to obtain. If you have a multi-meter that can measure microamps, I would be interested to see what kind of flame signal the unit is producing. There are tons of other things that can cause a flame signal error code that aren't related to the flame sensor itself. Plugged burner cross-overs, poor gas pressure setting, improper grounding, a cracked heat exchanger. I would love to know what a before and after microamp reading is on that sensor when cleaning though.
I'm confident that there will always be people who either don't feel confident enough to try this themselves or can't be bothered, and that's fine! Things like this are great in a pinch, however there are legitimate safety inspections that should be performed on all HVAC equipment to make sure there are no hazards to your health or safety. Specifically risks of fire and carbon monoxide leakage.
No such thing as a silly question! You don't *technically* have to turn off the gas to the appliance when you pull and clean the flame sensor as long as you have the power off. HOWEVER, it's always best practice to turn off both the gas and the power to the appliance when servicing it!
Quite a few things can lead to this. Are we sure that the gas valve is opening and letting gas flow to the burners? Are the burners plugged with gunk so even though the gas is flowing it's not igniting?
The flame sensor is not the same as a spark ignitor. A flame sensor is a control device designed to rectify the flame signal, not ignite the flame. The system in this video uses a hot surface ignitor to light the burners, not a spark ignitor. I have a separate video about how the hot surface ignitor works. While a spark ignition assembly also needs to be cleaned like we did in this video, you would't want (or need) to be touching it while it's trying to light.
Mentioned that in the video, that's pretty common. I was in a crawlspace the other day and didn't want to climb back out to get my brush, so I used a $50 bill from the previous client!
