Cracked heat Exchanger??

Old 02-19-05, 12:16 PM
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Exclamation Cracked heat Exchanger??

How do I confirm a contractors observation of a cracked heat exchanger. The flame roll out switch tripped cutting off the gas and the furnace blew cold air. Called a Heating/Cooling contractor immediately and he stated the heat exchanger was cracked and I needed a new furnace. Are there other things that should be checked first? If the heat exchanger is cracked, is it possible to replace just that component.

FYI- The furnace is currently not on at all for safety reasons.
Old 02-19-05, 01:10 PM
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If the heat exchanger is cracked, is it possible to replace just that component.
Yes it sure is . How old, could it be under a warranty yet??

Find out for sure if cracked. You dont want to run it like that with a crack.

Can try with burners on and before fan comes on turn blower on fan on. Does the flames change ? Blow around like??
Furnace: heat off put hand in and around burners turn blower on feel anything.
Then we have smoke bombs that you can get and put in it.
Run out and get a Carbon Monoxide alarm righht now for sure

Old 02-19-05, 02:23 PM
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Like Ed says, yes the heat xchnger can be replaced but depending on the age of the furnace it may not be worth it. I talk to a guy whos company if they suspect a leak they will pull the xchnger and if it's cracked and you buy a furnace from them they wave the inspection fee and if it ends up not being cracked they put it all back together and you just got a free furnace clean and inspect. Run this idea by them and they may bight if they're dure it's cracked.
Old 02-20-05, 12:04 AM
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I shut don about one half of the vents in the house then start the unit and watch it if the heat exchanger is cracked it will more then likely shoot out flames from the heatexchanger that is cracked then you can look at the cell with a mirror.
You may have an airflow problem as well.
So i would check to see if you have proper duct work and a clean passage through the unit.
Old 02-21-05, 08:22 PM
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You might check with the local gas utility company in your area. Some will do a free check of your furnace and give impartial advice, as they do not stand to make a profit by condeming your appliance, and selling you a new one. Sounds like your furnace may be in pretty bad shape if it does in fact need a heat exchanger. Flame roll out(which causes the "heat switch" to trip) can also be caused by dirty burner chambers or a "sooted" heat exchanger in which a simple cleaning will do. Large cracks are sometimes obvious and all else can be checked with the smoke test. Replacing a heat exchanger if possible is not always cost effective. Kind of like a heart transplant on a 90 year old. The liver goes bad the following year....
Old 03-01-05, 12:02 PM
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Does your furnace have inshot burners, like a jet with the flames going into the heat exchanger horizontally, or regular burners where the flames rise off the burners vertically? If the contractor visually observed something that leads him to believe there is a crack then you should be able to visually observe the same thing. Get someone to pull it out if there is any doubt, but this will cost you money which would be pretty much sunk if there is in fact a crack. Just describe what you see here or take a picture(if that is possible,,?)

Get the gas company out to give you a second opinion. It should be free.
Old 03-01-05, 02:47 PM
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Make sure the exhaust vent isnt clogged

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