Thanks Tad, you're very thorough and that is why you found the cracked heat exchanger, too bad for the customer but good for their health and safety, they were lucky to have you as a service tech.
I have a furnace with 140 limit switch open, now I can believe it is a cracked heat exchanger. I was speaking with co worker over phone and found it. Thanks for the info.
This was one of those that start out small but cost the customer dearly in the end. You did save the customers and families life. Finding that heat exchanger full of cracks , praise the Lord. Hallelujah.😊😊
good Job guys, I am an HVAC tech with few years of experience and i just came accross your video out of bordom amd wanted to appreciate what you are doing, keep it up
Very good explanation, I'm retired now after many decades in hvac. I REALLY LOVE IT AND WISH MY KNEES WOULDN'T HAVE GONE BAD ON ME. ALLWAYS USE SOME KIND OF KNEE PROTECTION.!!!!!
Thank you so much for this. I live in Iowa and we recently had 100 degree weather and my ac went out. Now the heat has passed ive found this and after replacing multiple parts (one was actually broken) this helped me truly troubleshoot and confirm. People like you posting these educational videos are real heros to people like me struggling to get by and unable to afford to hire someone.
I really appreciate you. Thank you so much for watching the videos. I'm so glad you let me know how i've helped and that to me means everything you're the.Reason I keep doing these videos
I learned a lot from this video. The biggest thing is the way to check in the limit switch is open with the thermistor, thought that it was only used to find super heats
That's a costumers are looking an a Technician a true if not the good one but find the heat exchanger a crack that saves the family life but at the end it costly damage to the pocket but money is money life is important. I'm retired but still looking to learn something good. From Toronto Canada good job Taddy. Keep up the good work to help costumers.
Tad, you guys in Tennessee really know your ac/heating trade. im glad i follow you bc even tho ive been doing this for 22 years in Fl so no gas furnaces much, i learn something new from you each and every time, cause and effect! Thanks for sharing.
I've been doing this for about about 20 years or more and I always add to returns to the big 90s like that. That dirty coil also could have contributed to that bad exchanger. But I would have never probably caught that without breaking it down myself because it had a rich nice blue and white Flame. In my experience over the years usually when that boy cracks I get some orange in the flame. Thanks for the tips I'll add this in my notes of troubleshooting. Love your content you do an awesome job peace and blessings😂
Your video was amazing from start to scratch, well explained, i bet you a camera scope would not find that crack, hard to find cracks with a camera, but you did everything the right way, good job!
Awesome video. I’m gonna rewatch and take notes. I’m an hvac student in Florida and I am confused about direction but you helped me with information thank you.
Man, I like and enjoy very much your teaching scenarios, and troubleshooting a lot. I do HVAC but not like you residential/commercial. I only do apartments complex and pretty much is the same each day, since is the same property. Every once an awhile I do City Residential. But definitely I'm learning and keep learning by watching your videos. You're the best!
Considering the space above the units most of the time, i never understand why not lift the unit up and take return from the bottom as well. Good catch on that HX
Very informative and well done video. All the right talking points. I learned a lot. Having come from an Industrial HVAC background, I feel that I have a lot to learn in the residential/commercial sector where I now own a business. This was very helpful. Walla Walla Washington.
A better filter will keep those heat exchangers clean!! 😊 I’ve been doing HVAC for 17 years, I’m located in Eastern middle Tennessee. You make really great videos! Keep it up!!
My furnace stays running nonstop but blows no heat. You can feel the warmth by the vent but no warm air blows. I had two servicemen come but they only offer me to buy a new furnace from them. So far no repair yet. I hope its okay for the next 2 months. Damn they say board is bad $600+, fan motor bad $1000+ and need a new thermostat cuz mine has mercury., and a new furnace will run $4200+++ not including yearly service cleaning. I like to just get it repair but not having to buy a whole new furnace when not necessary... Is there any honest repairman out there???
My boss and the customers think I should be able to do all this in like 20 minutes, by myself in a cramped attic space. lol You pretty knowledgeable tech Taddy. love your vids.
It is helpful to see someone else take time to find out the root problem and not just try and quick fix the symptoms. The part was telling of another fault. Excellent
You explained that very well and a lot of helpful information for young technicians learning the trade. My name is Eric and im watching your videos from Baltimore Maryland.
Really great informative video. I'm having an issue with my garage furnace my cousin sent me this link. I'm a plumber in illinois. The garage heaters a lot different it's one of those ceiling hung units. I changed the limit switch thinking that was the issue. It's not. I'm going to run some tests and check out the coil but this thing just keeps on shutting off on me. I was also going to try and change the thermostat. This thing was working fine and then it just started shutting off after 5 minutes of operation.
dam thats a big ass crack. i always put a box for 3.5 ton ac or anything at a 100kbtu and over. you offered to fix first before replacment. i beleive in building value with the client. when they see you actually care they will throw whatever you offer them. good work. im from illinois lol
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.
The thermistor was getting hotter then the rating on the limit because it was possibly sticking in to far. That furnace as most Carrier brands use a baffle to direct the air flow directly at the high limit to cool it off. I’d recommend using a piece of tape to hold the thermistor directly on the limit so it sees what the limit does. Nice find on the plugged secondary. Carrier also put out a bulletin for some of there units showing the insulation deteriorating and puffing up inside the primary section of heat exchanger and directly under the high limit the insulation puffs up and blocks a portion of the air from the blower motor even though the baffle is blowing it directly at it, causing nuisance limit trips. Their solution is to remove the limit and cut half-inch strips of metal tape, approximately 4 inches long and put them through the whole of the limit to secure the insulation back to the jacket. No more limit trips. This bulletin is posted and available.Heil is a carrier brand. Great video thanks.
Hello, do you have some reference material to look at. I am having the same issue. The furnace blower was getting suffocated by the loose insulation above blower motor. The board showed code 33. I removed the loose insulation and still get code 33. I’m planning to replace the limit switch. The gas burners shuts off after couple of minutes. The furnace is about a 4 years old.
@@BigCivilSac I was only referring to what I saw in the video and expanding on what he had done or explained. Unfortunately I have not diagnosed your situation so I wouldn’t be able to offer and useful information. I’d suggest calling a professional in your area. Good luck.
I do what you do but I just pull one screw out of limit then stick my “k” type thermometer through that. Or pull limit, foil tape, then poke thermometer through. 😅 100 ways to skin a cat🤷🏼♂️ I’m in year 3 an always refer to your videos, thanks for helping us all out🤘🥃
Hey, if the return was too small then that could definitely have contributed to the short cycling of the heater and a cracked heat exchanger over time. Evap coil could have been dirty too. Good pointers. It's always my last measurement static pressure and too often I wish I would have went straight to it. That man needs a new unit. Good find.
Yes! Taddy So much info. here! This Really Helps us who are out in the field troubleshoot, and be observant to the symptoms we see and the study we've done on heating and A/C. Very Good Video! Thanks! @@TaddyDigest
Sir, that was just about the most helpful vids I have seen in a loooong time. Thank you. Saved me a world of headache. BTW I love those Maxi Flex gloves - all I've been using.
I always sell a high efficiency air cleaner with 90% of my jobs, yes even mobile homes. Saves a whole bunch of service calls. All you have to do is take a garden hose in through coil area and flush the coil and he out with foaming evaporator coil cleaner and water. Add a pan beneath the blower area to catch the water.
There isn't enough dirt to consider that a blocked secondary heat exchanger. The most likely cause is undersized ductwork or oversized furnace. Installing a furnace of the same size will cause the same overheating problem if you don't address the true cause of the overheat problem. You need to include duct static pressure test in your troubleshooting . I do agree with you about needing returns on both side or 1 on the bottom for a 5 ton furnace
Just wanted you to know I followed every test in this video and found the secondary exchanger to be clean. Limit switch was 210 and thermistor showed 250 and if I remove the blower cover portion of the furnace the temp begins to rise past 250 so I have this feeling I’ll have the same outcome but this is now beyond my capabilities and I’m calling in a tech. January has to be the worst time to lose your heat 😢
I have the opposite issue with a furnace, it triggers the limit switch after a few hours of operation it shutdown. Could it be low blower speed, pressure is good, no returns or filters clogged
Instead of taking the front face off of the coil could you check with a camera threw the hole for the high limit or would that ever not be a possibility?
I have a 70k btu furnace and have more return. My furnace ran great for 28 years so I have already replaced all the components. This spring I will pull the heat exchanger and if it is even slightly bad I will shop around a find a new one. New furnaces don't last as long as the old ones. If I can get another 28 years off this one it will be somebody else's problem in the future. This only works if you can do this yourself.
I had a similar problem, but the furnace kept turning off immediately after the flame came on. I replaced the flame sensor and control board, and all the limit switches were all closed. What do you think the problem may have been?
If the return is too small then most likely the supply is too small and if that's the case adding a return won't solve your overheat problem and by the way, did you ever consider that the furnace is too big for that house?
Had a similar situation the other day, did it pull the heat exchanger but it was a twinned furnace that was overheating you think simple thing was going on? We found a bunch of leaves in the return plenum too.
The secondary heat exchanger looks not bad. You can see through it. I saw dirtier when people don't change a filter on time or don't use it. This one looks like new
Could you have done tested static pressure then from there used a carbon monoxide detector and would have picked it up through the supply registers that's what the heats from the cracked heat exchangers nit a lack of air flow..... t from az maybe? Just learning service and diag side myself been installing for 8 years
I haven't had many limit swich issue but the few i had was cracked exchanger and squirrel cage broke off the motor shaft. I would like to know how to do a combustion and static pressure test
I suggest to do a static test the 2nd heat exchanger does not look bad to trip the limit I guess it’s going to be not enough return air or a bad A coil thx brother
In this configuration, would it be fair to say that an air flow restriction would begin (excluding the filter ) at the secondary heat exchanger THEN the underside of the “A “ coil ???? If this is true, in cooling mode, the first place to look for a restriction would be just above the blower motor ???? Great video, learned a lot, never seen a 90% unit taken apart to that level before. Keep ‘em coming. Thanks again from NYC 👍👍👍
Great video man. Nice. My question is that if customer does not want to replace the furnace right away. is it safe to bypass limit switch temporarily. or if its too cold to survive...
Best HVAC video I’ve seen, you couldn’t have explained it any better. Thank you.
Wow, thanks!
@@TaddyDigest dude, you are better than any instructor I've had. Keep the videos rolling, you're gonna make me rich.
Really means a lot thank you so much
@@Caesar-nq5if For real! Most people would have never noticed the return size being the culprit but makes perfect sense. This dude is the HVAC GOAT!
Thanks Tad, you're very thorough and that is why you found the cracked heat exchanger, too bad for the customer but good for their health and safety, they were lucky to have you as a service tech.
I have a furnace with 140 limit switch open, now I can believe it is a cracked heat exchanger. I was speaking with co worker over phone and found it. Thanks for the info.
This was one of those that start out small but cost the customer dearly in the end. You did save the customers and families life. Finding that heat exchanger full of cracks , praise the Lord. Hallelujah.😊😊
good Job guys, I am an HVAC tech with few years of experience and i just came accross your video out of bordom amd wanted to appreciate what you are doing, keep it up
Great to hear!
Very good explanation, I'm retired now after many decades in hvac. I REALLY LOVE IT AND WISH MY KNEES WOULDN'T HAVE GONE BAD ON ME. ALLWAYS USE SOME KIND OF KNEE PROTECTION.!!!!!
Customer here. Nice video, i love learning how things work.
Thank you so much for this. I live in Iowa and we recently had 100 degree weather and my ac went out. Now the heat has passed ive found this and after replacing multiple parts (one was actually broken) this helped me truly troubleshoot and confirm. People like you posting these educational videos are real heros to people like me struggling to get by and unable to afford to hire someone.
I really appreciate you. Thank you so much for watching the videos. I'm so glad you let me know how i've helped and that to me means everything you're the.Reason I keep doing these videos
Best HVAC video I’ve seen, you couldn’t have explained it any better. Thank you.
I learned a lot from this video. The biggest thing is the way to check in the limit switch is open with the thermistor, thought that it was only used to find super heats
That's a costumers are looking an a Technician a true if not the good one but find the heat exchanger a crack that saves the family life but at the end it costly damage to the pocket but money is money life is important. I'm retired but still looking to learn something good. From Toronto Canada good job Taddy. Keep up the good work to help costumers.
Thank you very much for watching.
I am glad YOU are here
Tad, you guys in Tennessee really know your ac/heating trade. im glad i follow you bc even tho ive been doing this for 22 years in Fl so no gas furnaces much, i learn something new from you each and every time, cause and effect! Thanks for sharing.
Glad to hear that my brother please keep watching
That secondary heat exchanger was clean af bro.
I've been doing this for about about 20 years or more and I always add to returns to the big 90s like that. That dirty coil also could have contributed to that bad exchanger. But I would have never probably caught that without breaking it down myself because it had a rich nice blue and white Flame. In my experience over the years usually when that boy cracks I get some orange in the flame. Thanks for the tips I'll add this in my notes of troubleshooting. Love your content you do an awesome job peace and blessings😂
Thank you brother I'm glad you like to content. Thank you so much for watching.
No better in the business than ol Tadd. He's a master!
Your video was amazing from start to scratch, well explained, i bet you a camera scope would not find that crack, hard to find cracks with a camera, but you did everything the right way, good job!
Awesome video. I’m gonna rewatch and take notes. I’m an hvac student in Florida and I am confused about direction but you helped me with information thank you.
I'm about to get out of medical and back into HVAC. I'm addicted to this channel
Really appreciate you watching brother
@@TaddyDigest seriously, you are the Compressor Professor. I can't wait to start my LLC and I have you to thank
That's awesome the compressor professor 😄 🤣
Man, I like and enjoy very much your teaching scenarios, and troubleshooting a lot. I do HVAC but not like you residential/commercial. I only do apartments complex and pretty much is the same each day, since is the same property. Every once an awhile I do City Residential. But definitely I'm learning and keep learning by watching your videos. You're the best!
I'm glad you enjoy the video. You're the reason I do them my friend. Thank you so much for watching.
Considering the space above the units most of the time, i never understand why not lift the unit up and take return from the bottom as well. Good catch on that HX
Well done. It makes me dig a little deeper in my troubleshooting
Good to hear Glad you liked the video
I had a bad limit the other day. It was on a package unit though so it got corroded. Great video once again!
Very informative and well done video. All the right talking points. I learned a lot. Having come from an Industrial HVAC background, I feel that I have a lot to learn in the residential/commercial sector where I now own a business. This was very helpful. Walla Walla Washington.
A better filter will keep those heat exchangers clean!! 😊 I’ve been doing HVAC for 17 years, I’m located in Eastern middle Tennessee. You make really great videos! Keep it up!!
Good to know!
My furnace stays running nonstop but blows no heat. You can feel the warmth by the vent but no warm air blows. I had two servicemen come but they only offer me to buy a new furnace from them. So far no repair yet. I hope its okay for the next 2 months. Damn they say board is bad $600+, fan motor bad $1000+ and need a new thermostat cuz mine has mercury., and a new furnace will run $4200+++ not including yearly service cleaning. I like to just get it repair but not having to buy a whole new furnace when not necessary... Is there any honest repairman out there???
What MERV rating for a filter do you consider optimal for air cleaning but not too restrictive of air flow? Thanks!
Wow, fascinating. I've actually ran onto quite a few bad limits switches though for some reason.
Very informative, didn't realize that there was so much involved. Looks like keeping the coils clean is important. Thanks.👍
My boss and the customers think I should be able to do all this in like 20 minutes, by myself in a cramped attic space. lol You pretty knowledgeable tech Taddy. love your vids.
Your boss needs to get up there and do it himself
NTE bruh
The same thing happens with me 😏
Thank you.
AC coil was plugged.
Switch was doing its job.
Glad it helped
It is helpful to see someone else take time to find out the root problem and not just try and quick fix the symptoms.
The part was telling of another fault.
Excellent
The modern "health care" system works the symptoms and not root problems as well, and we know how healthy Americans are.
That was impressive diagnosis... Well done. Still scary though, fearing mine will dump out on me..
Thank you TAc I didn’t know you couldn’t add another return at the furnace if there is a water heater near by.
You're welcome my brother
Failed heat exchanger and a fist bump hahah, can't imagine why 😂 Good work guys.
Such a good diagnostics test/learning video. IM SUPER EXCITED
I hope you start posting TikTok from Mitchell SD because I used to fish 🐠 around there as a lived in SF
Your videos are liquid gold!!!!! Ty bud
Glad you like them!
You explained that very well and a lot of helpful information for young technicians learning the trade. My name is Eric and im watching your videos from Baltimore Maryland.
Really great informative video. I'm having an issue with my garage furnace my cousin sent me this link. I'm a plumber in illinois. The garage heaters a lot different it's one of those ceiling hung units. I changed the limit switch thinking that was the issue. It's not. I'm going to run some tests and check out the coil but this thing just keeps on shutting off on me. I was also going to try and change the thermostat. This thing was working fine and then it just started shutting off after 5 minutes of operation.
dam thats a big ass crack. i always put a box for 3.5 ton ac or anything at a 100kbtu and over. you offered to fix first before replacment. i beleive in building value with the client. when they see you actually care they will throw whatever you offer them. good work. im from illinois lol
it was very important for my education, thanks for your time from Chicago IL.
Great video, especially the cold air return tip.
great work and thank you, i am visiting you from Atlanta Ga. keep helping me be a more proficient technician
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.
Great service brother,good job 💯
Great job bro Pedro from Tampa FL leading every time with U.
The best HVAC guy
Nice troubleshooting & nice find on the heat exchanger ... Good info Tad ... Thx
Thanks 👍
The thermistor was getting hotter then the rating on the limit because it was possibly sticking in to far. That furnace as most Carrier brands use a baffle to direct the air flow directly at the high limit to cool it off. I’d recommend using a piece of tape to hold the thermistor directly on the limit so it sees what the limit does. Nice find on the plugged secondary. Carrier also put out a bulletin for some of there units showing the insulation deteriorating and puffing up inside the primary section of heat exchanger and directly under the high limit the insulation puffs up and blocks a portion of the air from the blower motor even though the baffle is blowing it directly at it, causing nuisance limit trips. Their solution is to remove the limit and cut half-inch strips of metal tape, approximately 4 inches long and put them through the whole of the limit to secure the insulation back to the jacket. No more limit trips. This bulletin is posted and available.Heil is a carrier brand. Great video thanks.
Hello, do you have some reference material to look at. I am having the same issue. The furnace blower was getting suffocated by the loose insulation above blower motor. The board showed code 33. I removed the loose insulation and still get code 33. I’m planning to replace the limit switch. The gas burners shuts off after couple of minutes. The furnace is about a 4 years old.
@@BigCivilSac I was only referring to what I saw in the video and expanding on what he had done or explained. Unfortunately I have not diagnosed your situation so I wouldn’t be able to offer and useful information. I’d suggest calling a professional in your area. Good luck.
Since this unit doesn’t have enough return duct, does it have enough supply ducts for this size unit
Hello sir. Just want to say I'm new to your channel and the content you present is excellent!!!!! Great Job!!
I do what you do but I just pull one screw out of limit then stick my “k” type thermometer through that. Or pull limit, foil tape, then poke thermometer through. 😅 100 ways to skin a cat🤷🏼♂️ I’m in year 3 an always refer to your videos, thanks for helping us all out🤘🥃
Hello, thank you so much for taking a time to make these videos. I learned so much from your videos. God bless you!!!
Toronto, Canada
Glad you like them!
Hey, if the return was too small then that could definitely have contributed to the short cycling of the heater and a cracked heat exchanger over time. Evap coil could have been dirty too. Good pointers. It's always my last measurement static pressure and too often I wish I would have went straight to it. That man needs a new unit. Good find.
That so good a really learn something. Thank you for sharing your experience
Here from southern Utah. Enjoy your show.
That is excellent so glad you're here brother
This was an awesome video!! I learned more here than I have in 6 months of school. Thank you Tad!!
I really appreciate you saying that you are awesome. Thank you so much for watching.
Please share the video if you have time and hit the like button.
Yes! Taddy So much info. here! This Really Helps us who are out in the field troubleshoot, and be observant to the symptoms we see and the study we've done on heating and A/C. Very Good Video! Thanks! @@TaddyDigest
Sir, that was just about the most helpful vids I have seen in a loooong time. Thank you. Saved me a world of headache. BTW I love those Maxi Flex gloves - all I've been using.
Thanks for posting this video I’m new to field and need these to learn I’m going to be paying for more details again thanks
Glad it was helpful!
I LIKE YOUR VIDEO, I 'M LEARNING A LOT FROM YOU THANKS, HI FROM CHICAGO IL.
thank you 😊
lol, at the fist bump on the cracked heatexchanger! make that money $$$ great video!
I remember yrs back ac kept freezing up with clean evaporator it was the secondary heat exchanger
Great job tad I had a high efficiency filter trip a high temp limit a while back always use cheap filters
That's a good idea!
I always sell a high efficiency air cleaner with 90% of my jobs, yes even mobile homes. Saves a whole bunch of service calls.
All you have to do is take a garden hose in through coil area and flush the coil and he out with foaming evaporator coil cleaner and water. Add a pan beneath the blower area to catch the water.
Good stuff brother
I like your style
i was interested in seeing how to clean the secondary heat exchanger, do you just brush it off or hose it down maybe?
Is that something you could find by measuring the cfms between supply and return?
yes
is it limit switch has anything to do with heat exchanger ?
There isn't enough dirt to consider that a blocked secondary heat exchanger. The most likely cause is undersized ductwork or oversized furnace. Installing a furnace of the same size will cause the same overheating problem if you don't address the true cause of the overheat problem. You need to include duct static pressure test in your troubleshooting . I do agree with you about needing returns on both side or 1 on the bottom for a 5 ton furnace
Just wanted you to know I followed every test in this video and found the secondary exchanger to be clean. Limit switch was 210 and thermistor showed 250 and if I remove the blower cover portion of the furnace the temp begins to rise past 250 so I have this feeling I’ll have the same outcome but this is now beyond my capabilities and I’m calling in a tech. January has to be the worst time to lose your heat 😢
I have the opposite issue with a furnace, it triggers the limit switch after a few hours of operation it shutdown. Could it be low blower speed, pressure is good, no returns or filters clogged
Excellent video teddy! What is the best way to clean that trap for 90% gas furnaces?
I’m Daniel from Chicago, good video hope you make more videos
Hey daniel you got it
Maaaaan you really go into Depth your Amazing God Bless Always
I appreciate that!
I learned not fist bump when I find a broken heat exchanger. But also thank you, great video.
Excellent, I learned a lot on this one. Thank you!
This was super helpful!! Thanks for making!
Nice job brother I learned a lot from this video
So glad to hear my friend. Thank you so much for watching
Would it be cheaper to replace the heat exchanger and clean the secondary over putting in a new furnace?
Yes
But to spend that much money on this old of a furnace is probably not a good idea.
quick question when removing that coil you have remove the refrigerant right? you also have to either cut the line or un-sweat right?
yes
Bro thank you, for spreading your knowledge u rock. I wanna become a super tech just like u.
You can do it!
Instead of taking the front face off of the coil could you check with a camera threw the hole for the high limit or would that ever not be a possibility?
Would measuring static pressure be worthwhile in this scenario?
Love watching your videos Taddy.
Glad to hear it
Great video with good knowledge. Thanks for sharing
Nice diagnosis, thank you
I have a 70k btu furnace and have more return. My furnace ran great for 28 years so I have already replaced all the components. This spring I will pull the heat exchanger and if it is even slightly bad I will shop around a find a new one. New furnaces don't last as long as the old ones. If I can get another 28 years off this one it will be somebody else's problem in the future. This only works if you can do this yourself.
I had a similar problem, but the furnace kept turning off immediately after the flame came on. I replaced the flame sensor and control board, and all the limit switches were all closed. What do you think the problem may have been?
check flame rectification
If the return is too small then most likely the supply is too small and if that's the case adding a return won't solve your overheat problem and by the way, did you ever consider that the furnace is too big for that house?
Great video but do you really want to pull air from an unconditioned space ?
Really depends
Can you please have a video on a digital manometer so to what water column setting is on the manometer
I have a few videos on that check out my how to set gas pressure videos.
Had a similar situation the other day, did it pull the heat exchanger but it was a twinned furnace that was overheating you think simple thing was going on? We found a bunch of leaves in the return plenum too.
Thanks for sharing
Good catch my friend
Thanks Brother
The secondary heat exchanger looks not bad. You can see through it. I saw dirtier when people don't change a filter on time or don't use it. This one looks like new
Brand new
This unit was less than a year old
@@TaddyDigest And it cracked heat exchanger ???
Great video. You explained everything just fine. Thanks!
Could you have done tested static pressure then from there used a carbon monoxide detector and would have picked it up through the supply registers that's what the heats from the cracked heat exchangers nit a lack of air flow..... t from az maybe? Just learning service and diag side myself been installing for 8 years
I haven't had many limit swich issue but the few i had was cracked exchanger and squirrel cage broke off the motor shaft. I would like to know how to do a combustion and static pressure test
Wait , wouldn't be the flame all jumpy from the cracked heat exchanger ?
Yes
Just had this same thing yesterday!
You’re the best. Thanks for the advice. 👍 my name is Bruno I live in Alexandria Virginia
Hey bruno i'm glad you're here brother
Stay healthy stay happy
I suggest to do a static test the 2nd heat exchanger does not look bad to trip the limit I guess it’s going to be not enough return air or a bad A coil thx brother
In this configuration, would it be fair to say that an air flow restriction would begin (excluding the filter ) at the secondary heat exchanger THEN the underside of the “A “ coil ???? If this is true, in cooling mode, the first place to look for a restriction would be just above the blower motor ????
Great video, learned a lot, never seen a 90% unit taken apart to that level before. Keep ‘em coming.
Thanks again from NYC 👍👍👍
Best video on UA-cam! I owe you dinner and a hand shake!
Wow, thanks
Great video man. Nice. My question is that if customer does not want to replace the furnace right away. is it safe to bypass limit switch temporarily. or if its too cold to survive...
Not safe at all
Never bypass a safety