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Carbon Monoxide Issue

Glen_7
Glen_7 Member Posts: 82
I posted this for a friend last year and the situation is still unresolved. Her CO detector went off when she started up her boiler the other day. It's gas fired and looks like a conversion. I don't have a pic of the burner unit but can post one if that helps. I told her to absolutely not turn the boiler on again and to get the chimney checked. That was done today and the chimney was clear but cleaned anyway and new cement applied at the vent/chimney opening. I've attached a picture of her vent setup to the chimney. If the chimney is clear, how else would CO be generated? She doesn't have a heating guy and her brother who is a general contractor plays around with heating but I don't trust his expertise. Any ideas? I know it's an old boiler but unless it HAS to be replaced now there are other priorities. Thank you.

Comments

  • Spence
    Spence Member Posts: 316
    It appears that you do not have the proper rise in your vent connectors for the boiler and DHW. The DHW even appears to be going downhill. Questions: Does the common vent have a cap? Can you photograph the external portion of the common vent so we can see the termination above the roofline? Have you had a combustion analysis lately for the boiler and DHW? Are they in an open basement?

    Remember that a common vent has to warm up in order for the gasses to flow at the proper rate. Sometimes the DHW can keep the CV warm enough, yet in a cold snap like that which occurs at the start of the season, the CV isn't warm enough to vent properly. Once the boiler is cycling this condition goes away provided the passage is clear and you don't have any conditions reflected in the questions above.
  • Jamie Hall
    Jamie Hall Member Posts: 18,903
    The question isn't how is CO generated -- it's always present in a combustion appliance -- the question is why doesn't it go out the chimney. That's what the chimney's for.

    So... step one: check your draught at what looks to be a huge barometric damper or whatever in the bottom of the breeching. You should have a good draught there.

    Then. How tight is this building? Is there adequate combustion air from some source, or is the building tight? If the building is tight and there isn't adequate combustion air, when the boiler fires all that's going to happen is that the exhaust is going to recirculate around and you will have CO issues. Are there any exhaust fans running somewhere else in the building? If so, and the building is a little tight, they may be pulling air down the chimney!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Zman
  • KC_Jones
    KC_Jones Member Posts: 5,081
    I'm going to throw out a couple "Captain Obvious" suggestions. Are you sure they cleared and cleaned the correct chimney? It looks like that house has 2 by the 2 clean out doors (I assume that's what they are). Also you state they put new cement on the flue connector. Did they actually remove it? To do a proper cleaning they must remove that to clean the bottom and make sure the metal portion of the pipe is clear (you would be amazed what can accumulate there. Another situation that I had on mine was that the metal flue was inserted too deeply into the masonry chimney and it couldn't draft correctly, it effectively reduced the size of the chimney to almost nothing. These all seem like obvious things, but mistakes I have personally seen. This is a dangerous situation so I think you will get a lot of input on this subject.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • icesailor
    icesailor Member Posts: 7,265
    Post more pictures of the boiler and the conversion burner.

    That looks like death waiting to go to the morgue.

    That's just plain wrong.
  • Glen_7
    Glen_7 Member Posts: 82
    I got her to call Scully (find a pro) and he came out today. He is going back to do some testing. I presume he will check out the venting, etc. Last year I did do a rather untechnical draft test with a piece of tissue and it did seem to draft ok. Thanks for all the responses so far.
  • Spence
    Spence Member Posts: 316
    Make sure he has a metric tissue.
  • icesailor
    icesailor Member Posts: 7,265
    Metric Tissue my hanky, someone needs to open the clean out door that doesn't appear to have been opened since being painted many Winter Solstices ago, (judging by the paint) and drilling a hole in the vent at the top of the boiler and checking the draft there. That big Oval take off isn't a new style draft/vent hood.

    When you remove a draft/vent hood from the top of a boiler, don't you usually replace it with a double acting draft control? That one has NO gate. And while you have the cleanout door open, look to see if the block webs are filled with mortar. Especially the top/above one. If the cleanout opening isn't parged tight, and the vent terminations above aren't tight and mortarted tight, you can loose a majority of the draft up inside the blocks and over to the next flue. With nothing left over for draft up the chimney.

    Where is this crib located?
  • Spence
    Spence Member Posts: 316
    Hopefully the contractor due to pay them a visit will get them squared away.
    icesailor
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    A Peerless JOT with a draft problem? No.....!
    A Peerless JOT with a gas conversion burner and a huge spillage hood? Yikes. Time for a pro!
    icesailor
  • billtwocase
    billtwocase Member Posts: 2,385
    Ditto Bob. Poster child boiler for a bad conversion. This boiler is plugged. Spillage hood looks more like soot spillage. You need a real pro ASAP
    Bob Bona_4icesailor
  • Glen_7
    Glen_7 Member Posts: 82
    Update-

    So I had a local heating guy from the find a pro section take a look. The CO in the boiler room was around 5 (I think) and the CO in the stack was off the charts. He took the burner off and said the cage fan? and air inlets were filthy. The mounts for the cage fan were also loose. He cleaned everything and put it back together and CO levels were now normal. Thanks for everyones feedback.
  • Glen_7
    Glen_7 Member Posts: 82
    Further to my update above, the pro did look up the gas gun and said the ductwork and hood was what was spec'd for that product. When he comes back he is going to install what I think he referred to as a spill switch. Chimney checked out fine.
  • Tim McElwain
    Tim McElwain Member Posts: 4,506
    Some older gas conversions did not always use a barometrics. Back then pre fabricated draft hoods for conversions were available and many times installers would use them. I still have all the tin nocker measurements to actually fabricate them. They typically had a built in slide which functioned as a draft control. It could be adjusted up or down inside the draft hood to balance out a proper draft.

    Just curious whose conversion burner is this and what is its model number?
  • Glen_7
    Glen_7 Member Posts: 82
    Tim- I'll try to check that this weekend and post a picture.