I need answers about gas furnace heat exchanger

Jim Mueller

I would like to know what are all the proper ways to check a 20-year-old furnace heat exchanger for cracks? Consumers Energy sent a company (Greater Detroit Heating & Cooling) to check my furnace for a noise it was making from my blower motor. When he was looking at it, he decided that he wanted to check my heat exchanger for cracks. He poured a large amount 4(64oz.) bottles of cold water into a running, hot heat exchanger. Is this the correct way? Do you think doing this would damage or crack the heat exchanger? If you think it would cause a crack, please EXPLAIN WHY or HOW in GREAT DETAIL. Your response and any help in this matter would be deeply appreciated.

James M. Mueller

Matt Undy

Why do you need answers? What happened? Did the tech find something and if so what? What are you trying to show or nto show? Colling a steel heat exchanger isn't likely to crack it, its too thin. It could warp something possibly making it no longer mate correctly with the rest of the cabinet or maybe open up a seam. I could also see it removing certain coatings or corrosion with the surface.

Your question is quite vauge, it would seem that dumping that much water on a HX is a very bad idea(except perhaps when it wasn't inside the furnace), but without some more clues there is no way we can guess if somehting was caused by the water or was already there.

Matt

R. Kalia

this is the 4th thread

He has now posted the same question four times. He does not appear to read the replies.

Ken_8

Jim,

Be advised this site is VERY active.

Unlike some sites, you may ask a question and get all the answers needed in an hour - not days or weeks!

If you wait a few days to see who and what the answers are - it may have already been answered by a dozen guys and drop off the board (Wall) because of all the other Q & A's that pre-empt yours!

You asked 2 and a half hours ago.

There's already three responses!
See?

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Dingo

roger that

.....

Oh welll

lchmb

actually

I think he is hoping for a different answer. I have a feeling he want's someone to say someone was wrong so he can go after a tech. And then use this thread to say "see told ya you were wrong!!" I would say that someone did a test and found a crack and he feel's it wasn't appropriate. If I am right then he should understand a 20 year old system is just that! Old and tired!!

Unknown

Mr. Mueller, I would like

to help you if possible. Please e-mail me at gastc@cox.net.

Matt Undy

He hasn't explained anough of what he thinks the consequences of dumping the water on the HX were for us to take any guess of if it did any damage or not. Personally i think it is likely to damage other parts of the furnace but not the HX itself.

I know many HXs only last 20 years or so but that is more an effect of poor design decisions on the part of the manufacturer than it being particularly old. Many last much longer.(I've supressed a much longer rant on the trnd of repalcing applinces becasue they're old and have had a small part fail).

Matt

Weezbo

I did mention this was unconventional method....

the others here are doing thier best to clarify that the equipment may have had a crck in it previously,the tech noticed Soot in the blower fan or worse Oil residue.
were it so the exchanger is toast.not only was it an indication of blowing co into your environment,the next thing that can occur is Fire shooting out of the supply vents!
water shouldnt hurt it however depending on the" where" of the cracks ,it could land the guy on his keester....
that would be his call,11000 v is severe stuff though...
I have seen horizontals submerged in a basement drained down and refired,same goes for old iron forced air units,boilers too.
smoke bombs and pepermint oil are easy cheap ways that i would advise a homeowner to check his system....

lchmb

didn't say

I didn't say that just because it was old it should be replaced. I am not in the buisness of just trashing yesterday's systems. I simply said that it appeared to me he wasn't happy with it being cracked, if it was, and he wasn't happy with the test procedure. I would say that if it failed after 20 year's he more than got his money's worth. As to design failure, I am not an engineer and wouldn't gander a guess. I have seen a multitude of system failure's and not to just one brand. I would say that a number of them were through manufacturing error's not design failure...:)

Jim Mueller

I have read all of the replies on Heat Exchanger

I am not trying to get anyone in trouble. I just want know if using that amount of cold water on a hot heat exchanger could make it crack. I know if your car was overheating and you add cold water to it, that it would crack it. I just want to inform them not to use this method on other people. I am trying to get them to stop using this method for checking for cracks in the future. Consumers needs to let experience tech work on furnace and not their people.

Thanks for all your help.

Jim Mueller

I have read all of the replies on Heat Exchanger

I am not trying to get anyone in trouble. I just want know if using that amount of cold water on a hot heat exchanger could make it crack. I know if your car was overheating and you add cold water to it, that it would crack it. I just want to inform them not to use this method on other people. I am trying to get them to stop using this method for checking for cracks in the future. Consumers needs to let experience tech work on furnace and not their people.

Thanks for all your help.

Arthur

Chesking h/E

An Auto engine usually has a Cast iron block and maybe Cylinder head. Or it may be Alumimum. Cold water on a cast iron is not recommemded as it can crack, A heat exchanger on a furnace is a steel and as Mat has already covered the subject well.
Cast iron is like a glass bottle you wouldn't pour a cold water into a Hot bottle, As matt says the worse that could happen is a warped chamber or open up a seam which is not likely.

Matt Undy

I'd be concerend about getting water into the controls and the bearings of the motors and blower too. If the bearings get water in them they won't fail immediately but weeks or months later as they corrode and the corrosion abrades away at the inside of the bearing.

Jon Eakes had a series on business size and risks and bennifits on hos show Just ask Jon Eakes. With a large company they have less control over the particular technician or even company doing your job so it is less likely to be done right the first time but they have the resources to get it done right(unlike a small contractor who may not be able to afford to re-do the job). Of course where gas is involved it has to be done close enugh to be safe the first time.

You might call Consumers Powers..er Energy. I know that Detroit Edison was good at getting back to me with someone who know what they were talking about when I wanted to know how they wanted an interruptable service installed. You should probably find somone who knows what the are doing now, before its an emergency. There is a good article on how to do this here somehwere (maybe somone else knows where it is).

Matt

Arthur

Water into H/E

I'd be very surprised if the small amount of water (considering the H/E was Hot which would vapourise most of the water) would get anywere near the bearings or the controls.

Matt Undy

He said that he poured about 2 gallons in there. I'd agree that small amounts aren't a problem if used carefuly.

Matt