Previous owner of our house had bypassed the temperature limit switch. A few years into us owning the home the furnace caught fire and almost burned our house down. Thank God for competent fire fighters and hvac guys that helped save the day.
Thank you. Because you put the step by step of how the heater started up. I was able to narrow down my burners weren’t firing. Pilot came on. Then I remembered I had a my coil pulled and cleaned. So I checked the gas line and sure as the sun is bright. The forget to turn the gas back on. I did, and within seconds the heaters roared to life. Thanks again
I have had a failure in the past that was similar to the symptoms you described, but it was neither of the switches you mentioned. My problem was the ignitor. It has burned clean thru. I later learned this is also very common on older furnaces.
Had a code 33 the other day. Flame rollout sensor had tripped because the air intake was blocked with ice. Cleared the ice and hit the reset button and that fixed it!
Great info - as a handyman I get intimidated by furnaces. I'm getting more and more calls for those "smart" thermostats that need a green wire (or some color) to be attached. Would you do a video on that? I'm sure there's an easy fix since I've done it with tech support on the phone, I'm just not sure how!
Yeah, there are a few different scenarios depending on the brand/model of smart thermostat. On a past house I just needed to run new wire to get the C Wire. ruclips.net/video/Af6aaUyMc3E/видео.html
The color wire doesn’t matter, what does is it needs to come from the common side of the low voltage transformer. All systems have a common side, but most older unit installs didn’t feed the thermostat with it. Most units are labeled C but some use X and some use other designations… an easy way to find it is to see what the condenser unit uses. One wire will be on the Y terminal, the OTHER wire will be C. Unless you have a package unit… then ya gotta follow the manual or schematic chart on the unit.
Had this happen was the role out opened. Actual cause was holes in the heat exchanger. Bottom line I purchased a new furnace. Helping the furnace man remove the old furnace found several large holes top of the exchanger. No CO detector went off.
The pressure on the two fans/blowers was set properly in this case, so that air leaked from inside your house and up the stack rather than the other direction. This is why the CO alarm did not go off. However if there was a filer partial blockage, stack blockage, or certain wind conditions, then CO and other gases from combustion would enter as air pressure difference goes the other way.
I've had this before! Wiring issue, I had no idea what I was doing, and I simply checked wires going to different things, found some damage after using a multimeter, and replaced that wire. Afterwards I learned it was the wiring going to these switches.
Overall good explanation. But step two in sequence of operation is pressure switch closes to prove inducer fan is producing proper amount of negative pressure. Pressure switch is normally open but closes after proving draft.
Great info and explanation. Did all the tests plus hot wired all sensors to confirm all good. Appears to be the gas valve/solenoid. Removed gas valve leads tested when gas is being called by igniters 27v across lines. Tested terminals on gas valve appears to be open line no resistance so probably bad solenoid. Would not have got there without the information you provided. Also tried light hammer no help. Thanks
I had a bad heat exchanger from a 21 year old Payne furnace that would trip the over-limit. The tech said it was a known problem with Carrier/Payne and while I could replace the exchanger only, he recommended just replacing the furnace. Mainly because of the labor involved. So that's the route I took.
My furnace does something like this. The fan turns on, the burners ignite, and all is well for a minute or two. After that, yhe burners will ignite and burn for 5 or 6 seconds and then go put. It's too long fir a bad flame sensor I would think. I bypassed my thermostat (it's a nest, I turned off eco and assistant) by connecting the red, white and green wires. Still the same problem. When I only connect the red and white wires, the furnace works fine. I've cleaned my flame sensor (was pretty clean to begin with) and made sure it was tightly mounted with a good wire connection. I've got a hvac technician coming tomorrow but I like to figure out things myself. Thanks for the video.
Could be that the open vent/air flow switch got tripped. Or some other safety switch. Once they are tripped, you will be to resolve then manually reset the switch. Hour to test can bad between devices. Like mine requires the thermostat to be set to not send a signal to the furnace, then turn off the power to the furnace vid the stock on the side of it, wait 3 minutes, turn power back on to furnace, wait 3 minutes, then set the thermostat to send a signal to the furnace.
Y do know, your furnace has several issues needing to be addressed, right? You have condensate leakage from your inducer, you have the dreaded Honeywell smart valve, with low voltage hsi… you have a lot of rust precipitation in the burner area. I will watch the full video and see if you mention the issues.
Yeah, overall this unit has done well but will need to replace sooner rather than later. I would not be surprised to get a crack in the heat exchanger in the next year or 2.
Great video.Thanks. To start with, my problem was originally, the furnace was not coming ON, there lights were blinking three times. The tech said I need to change my inducer motor.I changed it and also the pressure switch. The furnace started working, the blue flames were on. But there is not much hot air, my Trane system was blowing mild hot air . I watched this video and I was getting ready to order the two switches. Now my trane went back to how it was before I changed the inducer motor, the furnace probably worked for about 12 hours . The inducer motor is running, no flames. Any suggestions on what should I do.
In a 16 year old Mobile home. Heater stopped blowing, called a professional. After checking this and that he determined my blower had taken a dump. My 2 choices were 1. for 800plus or 600 plus,, chose the 600 since I'm a old fart not expected to live another 10 years so what the hey!!!! Did they screw me? Possibly. Heater is still working fine so far.. I don't know you sir but I trust you more. Just saying..
Yeah, that same furnace the blower motor went out and just the motor was $225 for parts. I swapped it out and has worked well for a year so I am sure if I hired it out the cost would be at least $600 so you probably got a fair deal.
could you Please advise? Heat filter is Clean, New so not that… I put the heat on 68-70 depending on temps of course- blower motor runs but not long, only blows out Cool air NOT warm or Hot and Thermostat will often go down to 65 or even 62 🥶 overnight as well (28 degrees here overnight last night), house is COLD unit is Older… I “think” the ignitors are working… could the Thermostat be the issue? it is one of this more modern ones (digital)
I converted a natural gas furnace to lp gas and can't be sure how to use my duel port manometer so far as what settings on the manometer. I know pressure in needs set at 11" water column, coming in to the valve, and 10" to the manifold. I don't see a wc setting on my manometer. Can I use psi setting? 0.36 and 0.40
What if it blows hot air on on mode until it reaches temperature, then just blows room temp air, and on auto mode just blows room temp air? Thanks so much
Can you do a video on how to safely remove broken baby safety plug covers. I have 3 different outlets that broke when I tried to remove the cover and now have one of the prongs stuck inside the outlet. Or does the outlet have to be completely removed? Help
I have a furnace that the fan keeps running after the heat is satisfied or turned off. I incorrectly replaced the fan limit switch because the fan would go off after a while. Still having an issue, I have a board coming now..
Actually, throughout North America you must have a license to do anything on a furnace that requires you to use any tool. with the exception of changing or cleaning an air filter
@@OmniscientWarrior No, you are not free to do so. Anything involving natural gas, propane or fuel oil requires the relevant ticket as per my previous comment. Don't believe me, look up the relevant laws or ask your home insurance provider.
The big reason your furnace is going out on limit is the use f that filtrate high density air filter… you NEVER use them on a side intake slot… only on a well designed filter action system. Do your furnace and blower motor a favor and change back to a 30day merv 4 filter…
Our furnace has been on the fritz for a few days now. Code is 3 LED flashes....induced draft blower automatically comes on and runs continuously but there's no heat. In my troubleshooting chart, it says fault description is pressure switch circuit not closing. Names off several possible causes. Last year, a hose was clogged to the drain system...the unit would come on, but would not ignite. Can't afford to have anyone come check or fix it😔 Any suggestions?
After checking the sensors and cleaning things, you may have to reset the signal on the furnace. How to do that varies. Some are at thermostats to off, flip the power switch on furnace off, wait 3 min, turn furnace back on, wait the min, turn thermostat to on.
I checked all of my switches and everything looked good so I made a conclusion that it was the board. I could not find a local distributor that would sell it to me because I’m not a certified technician working for a contractor. What a bunch of crap! I’m not sure if this is just New York making more stupid laws or is this common everywhere? I was forced to call someone in to tell me I needed a new board and install it. My hot water heater also just sprung a leak recently so I thought that I would switch to a tankless. Same deal. Home Depot didn’t have any in stock so I tried a distributor. Not certified! No sale! I got another tank at Home Depot.
There are many of online sources for buying control boards and other HVAC parts. Purchased a board for my girlfriends gas furnace from Amazon a few years ago. Technician wanted $700. Purchased a new one for $80 !
Most wholesalers only sell to contractors because that is what wholesale is for. You are not their customer, the contractors are. They are not going to sell you a part wholesale, but some distributors will sell you a part for retail depending on their policy and how the associate feels. Just like how a contractor cannot call the factory and get a part shipped to their shop, but the distributor can.
I like your videos, BUT working with a gas heater is Dangerous! I would not recommend people work on their own units past checking the air filter. I have done handyman work but until I went to school for HVAC I would not work on a heater. Put more disclaimers up, please.
And you are part of what is wrong with repair industry and why companies like John Deere and Apple try to say people can't do their own repairs or why they can't pick their own third party repair companies to fix stuff.
@@OmniscientWarrior I'm talking about safety..you have no clue what I'm talking about. Liability and insurance not do you have a right to screw with your furnace. You are looking from a consumer perspective. Do you know what those parts do and what can happe?smh
Previous owner of our house had bypassed the temperature limit switch. A few years into us owning the home the furnace caught fire and almost burned our house down. Thank God for competent fire fighters and hvac guys that helped save the day.
Wow! The negligence!
Thank you. Because you put the step by step of how the heater started up. I was able to narrow down my burners weren’t firing. Pilot came on. Then I remembered I had a my coil pulled and cleaned. So I checked the gas line and sure as the sun is bright. The forget to turn the gas back on. I did, and within seconds the heaters roared to life. Thanks again
I have had a failure in the past that was similar to the symptoms you described, but it was neither of the switches you mentioned. My problem was the ignitor. It has burned clean thru. I later learned this is also very common on older furnaces.
Had a code 33 the other day. Flame rollout sensor had tripped because the air intake was blocked with ice. Cleared the ice and hit the reset button and that fixed it!
This is the clearest how to video on troubleshooting a furnace! Thanks!
Thanks for the feedback!
Thank you. You helped me a lot.
Great info - as a handyman I get intimidated by furnaces. I'm getting more and more calls for those "smart" thermostats that need a green wire (or some color) to be attached. Would you do a video on that? I'm sure there's an easy fix since I've done it with tech support on the phone, I'm just not sure how!
Yeah, there are a few different scenarios depending on the brand/model of smart thermostat. On a past house I just needed to run new wire to get the C Wire.
ruclips.net/video/Af6aaUyMc3E/видео.html
The color wire doesn’t matter, what does is it needs to come from the common side of the low voltage transformer.
All systems have a common side, but most older unit installs didn’t feed the thermostat with it.
Most units are labeled C but some use X and some use other designations… an easy way to find it is to see what the condenser unit uses. One wire will be on the Y terminal, the OTHER wire will be C. Unless you have a package unit… then ya gotta follow the manual or schematic chart on the unit.
Had this happen was the role out opened. Actual cause was holes in the heat exchanger. Bottom line I purchased a new furnace. Helping the furnace man remove the old furnace found several large holes top of the exchanger. No CO detector went off.
Yeah, this unit is getting there and I see a fair amount of corrosion around the exchanger 😬
The pressure on the two fans/blowers was set properly in this case, so that air leaked from inside your house and up the stack rather than the other direction. This is why the CO alarm did not go off. However if there was a filer partial blockage, stack blockage, or certain wind conditions, then CO and other gases from combustion would enter as air pressure difference goes the other way.
I've had this before! Wiring issue, I had no idea what I was doing, and I simply checked wires going to different things, found some damage after using a multimeter, and replaced that wire. Afterwards I learned it was the wiring going to these switches.
Nice work 👊
Overall good explanation. But step two in sequence of operation is pressure switch closes to prove inducer fan is producing proper amount of negative pressure. Pressure switch is normally open but closes after proving draft.
Hey Robert, good point on the callout for the pressure switch. Appreciate the help.
Great info and explanation. Did all the tests plus hot wired all sensors to confirm all good. Appears to be the gas valve/solenoid. Removed gas valve leads tested when gas is being called by igniters 27v across lines. Tested terminals on gas valve appears to be open line no resistance so probably bad solenoid. Would not have got there without the information you provided. Also tried light hammer no help.
Thanks
my last mishap a few years ago was the hot surface ignitor burnt out *on the coldest night of the year* go figure LOL
That’s usually how it goes 🤦♂️
I had a bad heat exchanger from a 21 year old Payne furnace that would trip the over-limit. The tech said it was a known problem with Carrier/Payne and while I could replace the exchanger only, he recommended just replacing the furnace. Mainly because of the labor involved. So that's the route I took.
Great video. Lots of useful information. Thanks for sharing your knowledge.
You just saved me hundreds of dollars and a cold house.
My furnace does something like this. The fan turns on, the burners ignite, and all is well for a minute or two. After that, yhe burners will ignite and burn for 5 or 6 seconds and then go put. It's too long fir a bad flame sensor I would think. I bypassed my thermostat (it's a nest, I turned off eco and assistant) by connecting the red, white and green wires. Still the same problem. When I only connect the red and white wires, the furnace works fine. I've cleaned my flame sensor (was pretty clean to begin with) and made sure it was tightly mounted with a good wire connection. I've got a hvac technician coming tomorrow but I like to figure out things myself. Thanks for the video.
high temp. limit switch. minnesota, new years eve. -14° f outside.. 2 weeks till a warranty service repair person could arrive.
😬 that’s no fun. What did you end up doing?
Enjoyed your video. My burners are not lighting.
Could be that the open vent/air flow switch got tripped. Or some other safety switch.
Once they are tripped, you will be to resolve then manually reset the switch. Hour to test can bad between devices. Like mine requires the thermostat to be set to not send a signal to the furnace, then turn off the power to the furnace vid the stock on the side of it, wait 3 minutes, turn power back on to furnace, wait 3 minutes, then set the thermostat to send a signal to the furnace.
I have a no 65 yr old furnace it hums before it kicks on and runs after flames out thanks lenny
By chance do you have a similar videos about fully electric furnaces
I do not, best of luck 👍
If all else checks out ok (wiring etc.), can a dirty evaporator coil cause a high limit error?
What's reason why oil burner motor fan burned out
If my flame rollout switch keeps popping does that mean my heat exchanger is bad or do I need a new switch?
Y do know, your furnace has several issues needing to be addressed, right?
You have condensate leakage from your inducer, you have the dreaded Honeywell smart valve, with low voltage hsi… you have a lot of rust precipitation in the burner area.
I will watch the full video and see if you mention the issues.
Yeah, overall this unit has done well but will need to replace sooner rather than later. I would not be surprised to get a crack in the heat exchanger in the next year or 2.
Great video.Thanks. To start with, my problem was originally, the furnace was not coming ON, there lights were blinking three times. The tech said I need to change my inducer motor.I changed it and also the pressure switch. The furnace started working, the blue flames were on. But there is not much hot air, my Trane system was blowing mild hot air . I watched this video and I was getting ready to order the two switches. Now my trane went back to how it was before I changed the inducer motor, the furnace probably worked for about 12 hours . The inducer motor is running, no flames. Any suggestions on what should I do.
In a 16 year old Mobile home. Heater stopped blowing, called a professional. After checking this and that he determined my blower had taken a dump. My 2 choices were 1. for 800plus or 600 plus,, chose the 600 since I'm a old fart not expected to live another 10 years so what the hey!!!! Did they screw me? Possibly. Heater is still working fine so far.. I don't know you sir but I trust you more. Just saying..
Yeah, that same furnace the blower motor went out and just the motor was $225 for parts. I swapped it out and has worked well for a year so I am sure if I hired it out the cost would be at least $600 so you probably got a fair deal.
Thanks
My tech guy told me to just buy a heat exchanger. I want him to come check first to make sure. He says he's pretty sure.
Yeah, that isn't cheap so it would be nice to be sure prior to pulling the trigger.
I have the opposite problem my heater works but the blower has to have help spinning up, it sucks sticking hands in there to spin it.
could you Please advise?
Heat filter is Clean, New so not that… I put the heat on 68-70 depending on temps of course- blower motor runs but not long, only blows out Cool air NOT warm or Hot and Thermostat will often go down to 65 or even 62 🥶 overnight as well (28 degrees here overnight last night), house is COLD
unit is Older… I “think” the ignitors are working… could the Thermostat be the issue? it is one of this more modern ones (digital)
Thank you so much....
Failed burner was my main problem. It would not start, but was replaced.
How about water heater pilot not staying on for propane water heater has new thermal coupler
I converted a natural gas furnace to lp gas and can't be sure how to use my duel port manometer so far as what settings on the manometer. I know pressure in needs set at 11" water column, coming in to the valve, and 10" to the manifold. I don't see a wc setting on my manometer. Can I use psi setting? 0.36 and 0.40
What if it blows hot air on on mode until it reaches temperature, then just blows room temp air, and on auto mode just blows room temp air? Thanks so much
Flame detector gunked up… cleaned off the carbon and was back in business.
1.22.22 Thanks for the video.
Can you do a video on how to safely remove broken baby safety plug covers. I have 3 different outlets that broke when I tried to remove the cover and now have one of the prongs stuck inside the outlet. Or does the outlet have to be completely removed? Help
I have a furnace that the fan keeps running after the heat is satisfied or turned off. I incorrectly replaced the fan limit switch because the fan would go off after a while. Still having an issue, I have a board coming now..
Actually, throughout North America you must have a license to do anything on a furnace that requires you to use any tool. with the exception of changing or cleaning an air filter
Only of you are offering service as a technician. You are free to mess with your own stuff.
@@OmniscientWarrior No, you are not free to do so. Anything involving natural gas, propane or fuel oil requires the relevant ticket as per my previous comment. Don't believe me, look up the relevant laws or ask your home insurance provider.
I don't have a gas furnace, mine is electric. Would it be the same procedure?
No, but a lot of things with the same. No flame sensor but still a temp sensor for the heating element.
👍👍. Thanks!
You bet 👍
What if your flame does turn on but still blows cool air
The big reason your furnace is going out on limit is the use f that filtrate high density air filter… you NEVER use them on a side intake slot… only on a well designed filter action system.
Do your furnace and blower motor a favor and change back to a 30day merv 4 filter…
The actual failure was on another unit but many people shared a similar concern with High MERV rated filters.
Our furnace has been on the fritz for a few days now. Code is 3 LED flashes....induced draft blower automatically comes on and runs continuously but there's no heat. In my troubleshooting chart, it says fault description is pressure switch circuit not closing. Names off several possible causes.
Last year, a hose was clogged to the drain system...the unit would come on, but would not ignite. Can't afford to have anyone come check or fix it😔 Any suggestions?
I'm having an issue where my blower only blows cold air, not hot. The furnace is on, but it doesn't blow hot air.
After checking the sensors and cleaning things, you may have to reset the signal on the furnace. How to do that varies. Some are at thermostats to off, flip the power switch on furnace off, wait 3 min, turn furnace back on, wait the min, turn thermostat to on.
I checked all of my switches and everything looked good so I made a conclusion that it was the board. I could not find a local distributor that would sell it to me because I’m not a certified technician working for a contractor. What a bunch of crap! I’m not sure if this is just New York making more stupid laws or is this common everywhere? I was forced to call someone in to tell me I needed a new board and install it. My hot water heater also just sprung a leak recently so I thought that I would switch to a tankless. Same deal. Home Depot didn’t have any in stock so I tried a distributor. Not certified! No sale! I got another tank at Home Depot.
There are many of online sources for buying control boards and other HVAC parts. Purchased a board for my girlfriends gas furnace from Amazon a few years ago. Technician wanted $700. Purchased a new one for $80 !
Most wholesalers only sell to contractors because that is what wholesale is for. You are not their customer, the contractors are. They are not going to sell you a part wholesale, but some distributors will sell you a part for retail depending on their policy and how the associate feels. Just like how a contractor cannot call the factory and get a part shipped to their shop, but the distributor can.
7 minutes later. I’m still waiting for what I came here for. 🤦🏾♂️
Why my heat blows out cold air
Might have a similar failure mode to this video. Have you checked to see if there is a flashing LED on your control board.
I like your videos, BUT working with a gas heater is Dangerous! I would not recommend people work on their own units past checking the air filter. I have done handyman work but until I went to school for HVAC I would not work on a heater. Put more disclaimers up, please.
Wayyyyyyyyy toooo much talking. Let’s get to the possibilities of why no heat 🤦🏾♂️🤦🏾♂️🤦🏾♂️
don,t click on the link Scott its a troll i reported it
Thx!
what link ?
@@TrueAudio lol
😎✌🖖👍👌🤓
So you are teaching people how to mess with their rollout and limit? Yes! I'm a seasoned tech of 10 years. You shouldn't be teaching this
And you are part of what is wrong with repair industry and why companies like John Deere and Apple try to say people can't do their own repairs or why they can't pick their own third party repair companies to fix stuff.
@@OmniscientWarrior I'm talking about safety..you have no clue what I'm talking about. Liability and insurance not do you have a right to screw with your furnace. You are looking from a consumer perspective. Do you know what those parts do and what can happe?smh