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Cracked Heat Exchanger

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2lefthands
2lefthands Member Posts: 10
in THE MAIN WALL

My furnace has been short cycling for 2 years. I’ve had various techs to examine it and they haven’t been able to identify an issue. Consensus was “oversized, gets too hot, old.” It’s 10 years old.

Last week I called a new tech. After 90 minutes he discovered a cracked heat exchanger.

His advice was to immediately turn off the system and replace it. He warned that turning it back on can kill me with CO poisoning.

I have a newly purchased Kiddie CO detector next to the furnace showing 0. I believe it won’t register CO under 30 ppm. I have CO detectors through out the home that have never gone off.

How do I know if this furnace needs to be replaced immediately for safety reasons or if this is just an aggressive sales tactic?

IMG_9925.jpeg

Comments

  • Larry Weingarten
    Larry Weingarten Member Posts: 4,065

    Hi, I'd get some low level CO detectors right away, and just to be safe, don't run the furnace until they are installed. There might be some useful info here: https://www.forensicsdetectors.com/blogs/articles/low-level-carbon-monoxide-detector

    Yours, Larry

    Mad Dog_2
  • jimna01
    jimna01 Member Posts: 47

    By the time those hardware/big box store co detectors go off you could be dead or at least taking a bus to the nearest ER.

    mattmia2IronmanMad Dog_2
  • Ironman
    Ironman Member Posts: 7,899

    If the heat exchanger is cracked replacement is required.

    The CO detectors that you got at the big box store are worthless - except for paper weights.

    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    Mad Dog_2
  • 2lefthands
    2lefthands Member Posts: 10
    https://forum.heatinghelp.com/discussion/comment/1889547#Comment_1889547

    every item on the list you suggested is sold out

  • 2lefthands
    2lefthands Member Posts: 10

    can someone explain why regular CO detectors are worthless? If they are as crap as everyone says, wouldn’t the standard be low level detectors?

    Looking for constructive information.

  • HVACNUT
    HVACNUT Member Posts: 7,393

    What is that a picture of? I see a crack, but that doesn't look like a heat exchanger.

    What make and model furnace? What's the approximate square ft of the heated space? How did the tech prove the heat exchanger was cracked?

    mattmia2
  • pecmsg
    pecmsg Member Posts: 7,017
    https://forum.heatinghelp.com/discussion/comment/1889583#Comment_1889583

    UL Listed CO Detectors will not alarm until 70 PPM is exceeded for up to 4 hours.
    my personal CO detector alarm when 15 PPM is reached.
    https://www.myhomecomfort.org/wp-content/uploads/2015/09/CO_Levels_Risk_Chart.pdfThe

    Ironmanmattmia2Mad Dog_2
  • mattmia2
    mattmia2 Member Posts: 16,394
    https://forum.heatinghelp.com/discussion/comment/1889591#Comment_1889591

    i had the same question, i wanted the bigger view. it could be the fire side of a hx but it doesn't really look like a piece of metal that has been exposed to the heat of the products of combustion.(and even if it is, I don't think it would cause enough of a change in pressure to affect the combustion to cause short cycling)

  • 2lefthands
    2lefthands Member Posts: 10
    https://forum.heatinghelp.com/discussion/comment/1889591#Comment_1889591

    he showed me that photo and said “that’s your heat exchanger and it’s cracked” 2,000 to 2,400 square feet.


    IMG_9926.jpeg
  • HVACNUT
    HVACNUT Member Posts: 7,393

    I can't say for sure if it is or isn't. It doesn't even look like metal.

    If its an upflow furnace, and that looks like the blower fan on the right. Did the tech open the supply duct or remove the AC evaporator coil to get a down shot pic like that? Any other tests done? Draft? CO in the supply?

  • Mad Dog_2
    Mad Dog_2 Member Posts: 8,514

    Don't always assume technicians are gaming you..what if he is honest and correct? Is it worth risking your health or life? Mad Dog

    Consulting by Mad Dog & Matt Jr.
  • Jamie Hall
    Jamie Hall Member Posts: 27,206
    https://forum.heatinghelp.com/discussion/comment/1889583#Comment_1889583

    Regular CO detectors aren't really "crap" — it's just that the level at which they alarm is the "shut everything off and get out of the house" level. Which is useful to know… in a way…

    Low level CO detectors will warn of CO in the "moderate" range (10 to 50 ppm) which, to quote OSHA, will cause symptoms such as headaches and nausea over longer exposure; the OSHA limit is 8 hours. The problem is that the exposure time in a residence is longerr than that, and additional symptoms — particularly for older foils — can start to appear. Such as increased risk of heart attacks… it also appears to harm the brain in unborn or new-born children. somewhat subtler, however, is that it also, over those time spans, creates a sort of "brain fog" effect.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 20,063
    edited 2:25AM

    I don't know what the picture is showing but if it is the HX it does look like a crack and not some kind of factory seam.

    10 years old any warranty on the HX????

    My gut tells me if he spent 90 min looking for the problem and found that I would tend to think he is right.

    Someone out to sell you a furnace wouldn't take that long to condemn it.

    But need more info to tell.

  • Larry Weingarten
    Larry Weingarten Member Posts: 4,065

    Hi @2lefthands , I did a search on Amazon and got this: https://www.amazon.com/s?k=low+level+carbon+monoxide+detector

    The choices need looking at, but I'm sure you'll find something that fits the need. I think you need the information a detector will give, to have a better idea of what actually needs to happen next.

    Yours, Larry

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