Furnace Short Cycling - Solution

This KZbin video shows a furnace short cycling and how I resolved the issue. There can be several reasons a furnace will short cycle, from a dirty air filter, to a limit switch that fails open, or a failed or dirty flame sensing rod. 
⚠️Disclaimer:
I, Kevin Jones assume no liability for property damage or injury incurred as a result of any of the information contained in this video. This channel is for informational and educational purposes only! Use this information at your own risk. Always wear PPE and practice safe repair procedures when working with tools seen or implied in this video. Due to factors beyond my control, no information contained in this video shall create any expressed or implied warranty or guarantee of any particular result. Any bodily injury, property damage, or loss that may result from improper use of these tools, equipment, or from the information contained in this video, is the sole responsibility of the user and not Kevin Jones. By reading this, and/or watching any of the videos on this channel, you agree to the terms described herein. Do not attempt to repair a furnace if you are not qualified to do so!*
#furnace #furnacerepair #tips #homerepairs #homemaintenance #hvac #hvacmaintenance #facilitymanagement #facilitiesmaintenance #buildingmanagement #buildingmaintenance #howto #heater #troubleshooting #diagnosis #reliabilitycenteredmaintenance #preventativemaintenance #hvacservice #hvacmaintenance #hvactraining #servicetechnician

[@simmerthemdown]

This helped me out last year, but then acted up again. I didnt realize that the people and/or plumber swho worked on it before me, put the 2 ignition Pins in the opposing spots and the pins were then facing the wrong directions. I have no idea how it had been working mostly fine until now. but now it works even better than before. Good thing because i cant find any replacements for the flame rod or ignition pins, wouldnt have figured it out without ever seeing this video, so thanks.

[@kjfacilities-maint]

You’re welcome, I’m glad the video helped!

[@andyle2505]

Fixed my furnace because of your video. I cleaned both places you mentioned with steel wool and it worked! Much appreciated.

[@kjfacilities-maint]

That’s great, I’m glad you were able to fix it!

[@josephvipperman5057]

I like the commentary doing a great job of explaining everything

[@kjfacilities-maint]

Thank you. I appreciate your feedback!

[@FadeToBlack740]

I had this problem, cleaned my igniter and sensor but came to your video and saw about cleaning the barrels/where the gas comes through to actually ignite. Works fine now. Awesome video and I’ll be sure to keep up cleaning maintenance on all 3

[@kjfacilities-maint]

Thanks, that’s great. I’m glad to hear you fixed it!

[@rdwit659]

Thank you for the informative video.

[@kjfacilities-maint]

You’re welcome!

[@derrickgilzean9401]

Your vedio is really detail really good.

[@kjfacilities-maint]

Thank You.

[@aram4854]

Thanks for this video gonna go home and check on this

[@kjfacilities-maint]

No problem 👍

[@cbro777]

I cleaned my flame sensor last year and that seem to work. It's doing it again this year. Cleaning it this time wasn't helping. I did an ohm test on it and it was not consistent throughout. I ordered a replacement and will see how that changes things.

[@davidtrisha1469]

Good video im currently looking how to fix code 34. thats how i found your channel

[@kjfacilities-maint]

Hi David, there should be an error code legend on the inside of the cover panel of the furnace, usually next to the wiring schematic.

[@Hill4974]

This is a great video. I've cleaned my flame sensing rod and now my unit works fine. Thank you sir.🫡

[@kjfacilities-maint]

You're Welcome!

[@davesutton5721]

great video if u could get a close up on the connections u chek that would be good... now if i can just get my wife to say wow like that when i fix something.. thanks!

[@kjfacilities-maint]

Thanks for the kind comments.

[@Unsolicited-Info]

The sound overlays 😂

[@williamjohnson9282]

I cannot live without the cartoon commentary

[@kjfacilities-maint]

Haha :)

[@al52269]

Great video. Thanks for sharing. New subscribe here

[@kjfacilities-maint]

You’re welcome, thanks for subscribing and welcome to the channel!

[@stanleykowrach1957]

Solution buy house with electric heat. Pay more for heat but way less problems with safety sensors and values. 😢 Plus. Electric heat really warms a specific room

[@chillios2222]

got a goodman that does eeo and fo2 error , its a newer system typically the gas comes on and ignites , then it turns off , then it tries again, 3 times total, since its newer i wouldnt think it would be a flame sensor but it acts like it, i wonder would it throw a flame sensor type error if that was the cause?

[@kjfacilities-maint]

If the main burners are lighting, but not staying lit, I would inspect the flame sensing rod, if the rod has soot or carbon on it, gently clean it off with steel wool and see if it the burner stays lit now. Also, if you look inside the access panel, there may be an error code legend on the wiring diagram. Or, you can try typing your make and model and error codes into Google and you may find an error code legend.

[@marshallandroxy]

I've got short cycling on the a/c side, not heat, any tips/recommendations (a video like this but for ac etc..)

[@kjfacilities-maint]

Is your blower fan short cycling? Or is your outside compressor and/or condenser cooling fan short cycling?

[@pipi7731]

Where do you find a terminal connector that will fit that spade terminal on that item. I have found a few igniters with broken wires and because I couldnt find the connector I had to replace the igniter.

[@kjfacilities-maint]

You may be able to buy those wire harness connectors from an HVAC supply house, I have never had to replace those connectors. Like you, I just replace the entire igniter that comes with the new connector.

[@jaminjollo]

Auto parts store

[@lorenzovienna934]

Thank for the video. I had my furnace replaced 3 years ago and it was oversized. It countinued to over heat and shut off and turn back on right away. Ive had the technician out 7x now though out the install to try to fix. I was told by a different hvac tech that the has was tuned down to temporarily fix the over heating. Well now its in the negative cold snap here in Chicago and my heat cant keep up with the -10s and 20+degree windshield. Runs all night for few days stright sometimes dosent shut off. We went to bed and it was 74 degrees woke up and it was reading 68 degrees in the home. Had to buy a space heater to make it though last few days. Different techs who came out said the furnace installed was to large for my home. Also the return air duck was to small. They said the downstairs area could use a return because it dosen't have one. My question is, is this issue fixable and is the contract responsible for rectifying this problem with the correct size furnace. I have a warranty company that i use and they now said they aren't going to replace it, even though they admited to the contractor they used said the new units to big. My old furnace never had that problem before. Any recourse you can recommend be greatly appreciated.

[@kjfacilities-maint]

Yes, I would keep contacting the installer and your home warranty company until they rectify the situation. If they don’t want to replace the furnace with a proper size furnace then they should install the additional return on the first floor or increase the duct size. You can file a complaint with the Better Business Bureau too.

[@lorenzovienna934]

@@kjfacilities-maint thanks for the reply yes seems to be the route to go. I will go the BBB to see if anything changes

[@kjfacilities-maint]

Good luck!

[@suzibarton3269]

Okay I did all of this and its still shutting off..after starting and running for about 5 minutes...what would be your next suggestion I could check?

[@kjfacilities-maint]

Assuming your furnace is an 80% efficiency furnace, like the one in the video, make sure you check the following items: -change the air filter -Check for loose, broken, or corroded wire connections, especially the ground wires. -try cleaning the flame sensing rod off with steel wool -Make sure the flame sensing rod is completely engulfed in flame when the furnace is running. -make sure the pressure switch contacts are closed. -make sure you are not seeing any flame rollout when the furnace is running. -Inspect the metal exhaust pipe, make sure the outside termination is not blocked with leaves or a birds nest etc. -when the furnace shuts itself off, look at the flashing red LED light and count the number of flashes, then look at the inside cover panel of the furnace at the legend it should tell you what the error code is. -when the furnace is running, make sure you can hear the draft inducer fan, and blower fan running, they should sound quiet, no squealing, or grinding noise. -make sure none of your supply or return vents are closed or blocked with furniture or anything else. -make sure the thermostat is calling for heat and if you have backup batteries in your thermostat try replacing those too.

[@losttribe1993]

Change ur t stat. Maybe

[@suzibarton3269]

I replaced the pressure switch and fixed it all issues. Pressure switch is KEY to check...cheap replacement too@@losttribe1993

[@Thetileguy]

I follow all the steps furnace works back 10 min of my time save me some $$$

[@kjfacilities-maint]

Correct if the pressure switch does not close, or doesn’t stay closed, the furnace will not continue with the sequence of operation to light the main burner, or the main burner won’t stay lit.

[@trampledunderfoot3630]

My furnace started short cycling about a week ago. Set at 69, it would run just until the point where the room temperature would reach 69 then immediately the thermostat screen would go blank, the furnace would blow cool air for a couple seconds, then shut off. The instant the furnace would shut off, the thermostat screen would come back on. The screen would read 69 for the set temperature and 73 for the room temperature. After about two seconds, the room temperature changes to 68, the furnace would kick back on blowing warm air until the temperature hit 69 again and the thermostat would go blank and it would all repeat. I'd forgotten to change the furnace filters, and they were pretty dirty. I changed them, and it didn't help, the same thing would happen. I took the filters out, and the furnace and thermostat run normally no problem. I put one filter in, and it runs normally no problem. I put both filters in, and the problem starts up again. A couple of months ago my thermostat started flashing the word "battery". At that time, it was news to me that thermostats needed batteries. I opened mine up, and lo and behold there are batteries leaking acid. I took the old ones out, brushed off as much acid as I could, put new batteries in, and the thermostat worked fine. I thought it was a sure sign it was the filters when the furnace worked when the filters were out, but clean filters don't help. Could this be the thermostat or something else? If the problem weren't the filters, why would it work with the filters taken out? Thanks to anyone who has ideas.

[@kjfacilities-maint]

I would replace the thermostat because you mentioned some battery acid leaked inside of it. I would also double check the thermostat wire connections at the thermostat and down at the furnace to make sure they’re hooked to the proper terminals. I would also check the condition of the flame sensing rod if it is corroded, or has soot or carbon buildup gently, clean it off with steel wool. Does your furnace control board flash any error code?

[@trampledunderfoot3630]

@@kjfacilities-maint Thanks for responding! No error code, it's the green heartbeat that the manual says is normal. It has been a while since I've checked the flame sensing rod, I'll do that and order a thermostat. If it is the rod or the thermostat, how does it make sense that it works fine when the filters are removed?

[@kjfacilities-maint]

@trampledunderfoot3630 did you buy high efficiency filters? I recommend MERV 8 rated filters only, anything above a MERV 8, even when new can restrict airflow through the furnace too much, and cause problems.

[@trampledunderfoot3630]

@@kjfacilities-maint Yes, when I started changing the filters myself I found Merv 8 in there, and was afraid to change anything, so I always buy Merv 8. My furnace says to use Air Bear 16x25x5, and I did buy an off brand to save $. Maybe I should get the Air Bears? Maybe something else is causing it to overheat, but removing the filters just helps keep it cool? I don't know, beats me.

[@kjfacilities-maint]

@trampledunderfoot3630 The cheap MERV 8 brand should work just fine. If your furnace works fine without the filters in it, that would suggest an airflow problem. I would check the pressure switch, the tube that connects to the pressure switch to the furnace. Make sure all the openings are clear. I would check the condition of the flame sensing rod. Make sure it’s clean. I would make sure no insulation inside the furnace is getting sucked against the blower motor when it’s running too. Do you have a high efficiency furnace with a condensate drain line?

[@jackyee2370]

What happened when you force open the furnace. But the fan runs for one second and it turns back off. And on and off continuously

[@kjfacilities-maint]

I would troubleshoot the fan circuit... Could be an issue at the pressure switch, if the switch is good, it could be the motor or capacitor, or control board.

[@randybocelli6111]

Ok i have done all of what you had said. I have a goodman furnace i had a tech come out like 4 times he kept replacing parts. So new parts are inducer motor , control board. Temp sensor. And flame rod. The issue is the furnace will kick on and stay on between 3 to 5min. Then start over. No error codes Filter new. And pressure switch seems to be working. Would you have any idea what i need to check next

[@kjfacilities-maint]

Did he check the pressure switch? Did he check the tube going from the pressure switch to the flue box? Is your furnace a high efficiency condensing furnace? Does it have PVC supply and exhaust pipes? If so, it could be a problem with the condensation, check to make sure the condensate trap is cleaned out, the condensate drain line is clear, check outside to make Sure there is no birds nest or insect nest blocking the air supply or return. If the furnace gets its air from inside your house, make sure it has an adequate air supply. Did the tech check gas pressure at the gas valve?

[@randybocelli6111]

@kjfacilities-maint in not a high efficiency unit Pressure switch and hose good no clog have not checked the gas pressure Pretty much everything been replaced. All vents are clear. Just been crazy trying to figure it out. All connections seem tight but I can go thru again and make sure. I'm at a lost lol

[@kjfacilities-maint]

@randybocelli6111 is the new filter MERV 8? Has anything changed recently? Before it shuts off, do you hear or see anything unusual? Flames should be steady blue, no flame rollout. Does the thermostat have new batteries in it? Is the flame sensing rod fully engulfed in flame?

[@randybocelli6111]

@kjfacilities-maint not sure on the filter but I did take it out and tested still same issue. No roll out and the sensor is covered. It is a mystery that's for sure

[@kjfacilities-maint]

I’d check ground wire connections, make sure they aren’t corroded, loose, or broken. I’d also check to see if the gas valve loses its mili-volt signal from the flame sensing rod. I have seen gas valves go bad, but it is not very common.

[@taijikimura247]

Hello, I have a Carrier 80 and the furnace only stays on if I remove the new merv 8 filter. Once I add the new merv 8 filter, the heater stays on for 7 minutes and then I get a e74 error on my Nest and the heater stops. What do you suspect is the cause? Thank you.

[@kjfacilities-maint]

Is the nest thermostat newly installed? An E74 error code on a nest thermostat usually means a problem with the wiring to the thermostat.

[@taijikimura247]

@@kjfacilities-maintHi! It was installed 2 years ago. Weird thing is, when I remove the merv 8 filter, it works without any issues. But once I put the filter in, after 7 minutes, I get the Furnace Heads Up warning that it is short cycling. Thanks for replying back so quickly!

[@kjfacilities-maint]

Have you always ran a Merv 8 rated filter in it? Has anything changed with your system recently? Is it a 90% high efficiency condensing furnace?

[@taijikimura247]

@@kjfacilities-maintHello, I just moved into this house and replaced the old thermostat with a Nest. I am thinking to go down to a Merv 5. Do you think a Merv 5 is okay to use for home use? I also have a return vent by the hallway with a Merv 8. Thank you again 🙏

[@kjfacilities-maint]

MERV 5 would be ok too. However, the Merv eight filter should be working fine. There is only one return filter in the entire system right? Just the filter in the hallway? No filter at the furnace it self?

[@danbyrne6501]

I could live without the cartoon commentary

[@donaldbone7862]

Gas valve

[@renzgrand]

Thank You for me it was the steel air thermometer 🌡️

[@kjfacilities-maint]

You're welcome, I'm glad you were able to fix it!