A Simple Trick To See If Your Heat Exchanger Is Cracked.

Great tip for a DIY check. I am very impressed on your one handed match lighting skills :D

How do you keep your heat exchanger clean when you're literally pulling in are that contains pollen from the outside?

Yeah it's as simple as that. Every furnace is the same as this basic one. They dont actually create carbon monoxide its always just a big scam and millions of HVAC technician are just trying to scam you. Carbon monoxide detectors are 100% reliable and you can bet your life on it. The american gas association says any crack and it should be replaced but this guy says its fine. Its not like the exhaust pipes or combustion air pipes ever get blocked or the secondary heat exchangers ever get plugged up so the crack will never hurt anyone cuz the air Always goes in right? Let me guess, you have videos teaching people how to bypass safety switches as well? Are You putting lives at risk for clicks? I actually hate heating season for hvac because i dont like showing people they have a crack in their heat exchangers and they dont have a clue what that is or means except to watch out cracked heat exchangers = being scammed when they have a serious problem. So thanks to all the shitty techs out there and to people like you too that spreads misguided misinformation whether intentionally or not. You cant sum up all the various circumstances, types of equipment, environments, people, risks etc down to "its all just as simple as holding a flame inside here and watching it, thats all that matters". Id say 1-2% of hvac techs are dishonest or lack integrity, they dont speak for the rest of us hard working people that care about people's safety and having heat when its freezing and take extra calls to help more people. Also do you hear yourself? Your furnace is safe if the flame doesn't move? This test is okay as an indicator a crack might be present but not for determining if its safe or to say there is no crack. Isnt that just common sense?

Not the only way to tell if there’s a crack. If you visually see one then it’s cracked… this won’t always pick up on that

Friend, so is that a safe furnace or unsafe because of the dancing flame?

Good way to test for sure, but saying a technician is scamming you if they find a crack, but because its so small and not “doing anything” to the match flame is not true. In my province, if we find a crack, we are supposed to shut the unit down or risk our gas ticket. Basically a cracked heat exchanger in any way is supposed to be replaced.

The exchangers are made from heat-resistant metal sheets, they do not expand much, if they have cracks, cold and heat do not open and close the cracks too much.

Great video

Just a word of caution, I’ve been in this business for over 30 yrs. I’ve used the “match test”, powder puff into the burner tubes, manually disassemble and check with inspection mirrors and now also inspection cameras. There very well could be a hole or crack and you might not get a discernible flame action at the entry point of the tube. Most techs I know these days use a camera and can show you “live” what they find.
And no, a crack does not automatically mean CO will get into your living space. The problem is the potential is now there. And if you’re a tech checking and signing off on a furnace you have to make your decision on the side of caution.

Where was the crack? You clearly have infiltration. Why not show the crack too?

Where was the crack? You clearly have infiltration. Why not show the crack too?

I'm having a hard time understanding this. Under normal operation, when the inducer is pulling air through the combustion side of the heat exchanger, why is the match flame not dancing in that draft?

The flame/smoke test is a good one to perform, but I have an issue with one thing you said. Something along the lines of "a small crack that won't do anything." That is a seriously dangerous mentality to teach homeowners. If there is indead a crack, no matter how small it is or whether or not it will disrupt the flame at the time of testing, it is completely irrelevant. That small crack can and will grow. No matter how small a crack is, either the heat exchanger should be changed out or the furnace. If you're telling your customers a small crack is nothing to worry about, you're endangering them.

Thank you soooo much.

I wish that I knew this before I got a new system.

It might be worth noting that this should be checked with both a “hot” and “cold” exchanger as sometimes if there is a crack in it, once the exchanger warms up, the metal expands slightly.

awesome video really easy to understand and very straight forward thank you keep it up !

Good video thank you

Just watch the burners before and after the blower kicks on. The cracked cells flame will no longer just be burning in the burner tubes. Some of the flames will be burning outside of the tubes. The burner box will get hotter and hotter as the crack grows bigger. When the crack is to big your flame roll out switches will start popping.
You should be able to hold your hand on the burner box even after running ten minutes if it not cracked.

i just test out, i got very very little movement, but the lighter stay on with blower motor fan on. is it normal>? also mostly blue gas fire camout just like in the video.

It was a stroke of genius for you to include that 3D animation of how a heat exchanger is shaped.

Careful jumpering furnace terminal strips. If you have an older thermostat that has a mercury bulb inside it it has a small device called an anticipator that cycles the furnace off at the end of the cycle. A jumper will burn out that part! Then your furnace will short cycle…on and off instead of running normally. You will need a new thermostat. Careful with gas appliances. Find an honest contractor (lol) to service your equipment.

Yes this works for cracks but not for plugged heat exchangers.

Highly recommend that you purchase a wall mounted carbon monoxide detector and place it near the bedrooms in your home. Test it regularly and protect your love ones from CO2 poisoning.

Excellent explanation! Wonderful video.

Wrong on so many levels.. that is not the furnace date code.. and if your furnace is cracked, a good contractor will show you the cracks upon replacement. I've been in the hvac industry since 1992 and an owner operator since 2005.. your video is not accurate and you are putting home owners at risk

Thank you for putting up this video!
I was nearly scammed years ago by an HVAC guy who told me my furnace had a cracked heat exchanger. Even whipped out his "carbon monoxide detector" to show me the high numbers coming thru the vents. I asked him then why my multiple CO monitors all over in the house were not going off if there was life threatening levels - to which he shrugged off. Then he and his boss tried to pressure me into buying some off brand furnace replacement.
Fortunately I had to get to work at the time, so put him off until I had a chance to arrange the finances. I then got a recommendation from a friend at work for a different HVAC guy to come out and look at it. He found that not only was there NOT a cracked exchanger, but that the previous HVAC guy had "booby trapped" my furnace by manually destroying the computer board so the furnace would not run at all now. The cost of replacing the computer board on the old girl was almost as much as a new furnace, so I had the new HVAC company replace it with a well known brand.
Now I understand it better and will know how to check myself! Thanks!!

Not to be obvious, but I’d be making sure there are no gas leaks from the valve or fittings before doing this or you could end up putting a hole in your wall :/

Outstanding explanation!!!!! Thank you man!
I am a licensed hvac/refrigeration contractor. Will be sending this video to my customers! It’s the best and easy to understand video about heat exchanger issues that I’ve seen!
Thank you!

The hole you drilled was very close to where you held the match. What if the crack is higher up on the heat exchanger? Seems like it would be much more difficult for the fresh air to reach the flame. I wish you would have tested a couple of hole/crack positions.

Well explained and well done. You should it be a teacher because you take the time and I can see your devotion. Keep up the good work. Professor WG, US Army Retired/Disabled Veteran from Pennsylvania.

A real pro will always use a combustion analyzer ,print a strip and show you the results !! I use a testo 310

With that hole, it would have been good if you then re-connected the gas and showed what happened to the gas flame, too.

Seems like to me that you also jumped some safety features. A modern furnace will check for vacuum with an inducer fan. But yours can't do that and for some reason isn't turning off. hmm.

Is that a wssc sticker

Thank you for showing this,I need to check mine and was not sure how,good tip.

One of the best videos I have seen so far. Thanks for doing this video.

Thanks for posting this! I think an orange flame is not enough oxygen in the mix. Or is it too much?

Many thanks for all of your education. You are awesome in every regard. I am watching all of your videos. They are excellent. I wished you were my HVAC guy.

My neighbor’s furnace (mounted in their garage) is audible from a few houses down when it runs. Crazy loud. Could that be an indication their unit is underperforming or broken somehow?

Now that's some good info... Thanks?
Also saw the other video you mention, also good info.

You could have ran it one more time to show what it does to the burner flame

thanks for the info . never knew this test after fifty years in business.

How about diy fixes for a hole in exchanger.? A patch?

Very interesting. Would need to try this on a condensing furnance and also clamshell style chamber.

I realize you're showing home owner how to find leak
I suggest noting that looking closely at burner assembly could be dangerous if you had a large crack due to a large rollout condition. If I ever look a flame on start-up, I always have my hand on the gas valve shut off. And stand back a little further. Roll out sensor sometimes takes time for flame to migrate down to it to shut off gas valve.

Excellent lesson!

Thanks for the video ......good training

Excellent money saving info. You are the best!!!