Hmmm waterheater venting ok but still getting exhaust/combustion smell in cellar?

Discussion in 'Water Heater Forum, Tanks' started by vtxdude, Dec 8, 2009.

  1. vtxdude

    vtxdude New Member

    Messages:
    127
    Location:
    NH
    Well the HVAC guys came over and they fixed best they could the mess that the Sears plumber did on the venting...gave me much more vertical lift on the horizontal run and fixed where he had just thrown the 4 inch pipe over the 3 inch pipe(see my other thread jeeesh) It isn't pretty by any means but it seems to be drafting fine

    They are coming back on Thursday to add a 12" X 12" inch cold air return that they say should cure the negative pressure that my cellar experiences when the furnace is on.


    Now the drafting seems good on the water heater...I can cup my hands around the draft hood and not get burned or half to move them...but for some reason the heater is still giving off either and exhaust or combustion smell that seems to travel over to my stairs and up the stairwell where it gathers...it isn't CO afaik as neither CO monitors right near the WH register at all but it does seem to give me a headache if I'm down there for a bit.


    Any ideas or solutions?? I am at my wit's end...my next step I think is to pull the gas water heater out, ship it back to Sears and throw an electric one in it's place...exhaust issue solved


    Do I have any other options???
  2. Doherty Plumbing

    Doherty Plumbing Journeyman & Gas Fitter

    Messages:
    810
    Location:
    Penticton, BC
    Did they get rid of that goofy double 90 up and over thing to get up into the common vent?

    Also as I said in my other post in your thread.... A properly burning gas appliance emits NO carbon monoxide, only carbon dioxide...
  3. vtxdude

    vtxdude New Member

    Messages:
    127
    Location:
    NH
    No...the way things are set they could not..in fact there may be an extra bend in there...but it is drafting properly drawing etc..pipes are hot all the way up......flame is a bit lazy and loud on heater...so if it is not burning properly could it be emitting these fumes even if drafting is working properly?
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,268
    Location:
    New England
    If there are no leaks in the flue, and generally it is drawing well, you may have an air supply problem. ANy other burner assembly in the house can create a vacuum in the whole place, and make it hard for the gas to flow out the flue. Use of a vent hood on the stove, or bathroom vents, or even an improperly sealed or operating furnace can cause air pressure imbalences. ANy combustion device needs makeup air to operate. The newest ones use a sealed combustion system where they use two pipes, one to provide fresh air, and the second to exhaust the combustion by-products. You may just need to provide more air into that room.

    Gas combustion byproducts can give you a headache. If they also contain CO, they can kill you instead of just making you sick. Sounds like you either have a leak in the flue, or a makeup air problem.
  5. vtxdude

    vtxdude New Member

    Messages:
    127
    Location:
    NH

    What are some of my options??
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,048
    Location:
    Cave Creek, Arizona
    smell

    At this stage, we would have to be there to acutally smell what you are noticing, and also check the area to see if everything is proper. To illustrate the problem, I once had a customer call about a sewer gas odor in his house. We were there most of the day making every test possible without finding any possible cause for them. When it started to get dark in the bathroom I turned on the light. But then I had to go to a hardware store to buy something to make another test. When I returned the customer said the sewer gas odor had appeared again. When I went into the bathroom to check for myself, I smelled the odor, and told him, "That is not sewer gas, it is burning plastic." I checked the overhead light and it was charred. Sometime in the past he had used an oversized bulb which had scorched the plastic and everytime it got hot afterwards it emitted the odor. He installed a new fixture and got rid of the smell, but paid me megabucks for the time we had spent there.
  7. Doherty Plumbing

    Doherty Plumbing Journeyman & Gas Fitter

    Messages:
    810
    Location:
    Penticton, BC
    A lazy flame is usually cause by lack of primary air.....

    And the drafting has NOTHING to do with the products of combustion (not exactly but for sake of making things easy we'll pretend this is always the case).

    Once the HWT is fired up and running for a good 5-10 minutes hold a lighter up by the draft hood. The flame should get pulled in towards the vent. If you have flue gas spillage the flame might get snuffed out or will tend to be pushed away from the draft hood.

    And the more bends you have the worse off the venting will be it's that simple. In an ideal world every natural draft vent coming off an appliance would go straight up through the roof with no offsets.
  8. vtxdude

    vtxdude New Member

    Messages:
    127
    Location:
    NH
    yeah I hear you..I wish it was the case.....but unfortunately the way my water heater is situated I need the bends and and such :(


    How much more per year would an electric run me? This I guess would solve any exhaust issues

    So I could have perfect drafting and if the heater isn't getting enough secondary air I'm going to have combustion smells probably? Seeems like for the most part that the heat smell, whatever is rising from that first adjustable elbow...are those things sealed??

    Probably sounding naive but I'm trying to learn

    Flame is blue but has some yellow tips dancing and for some reason or other will burn orange for a bit at times


    Something must have changed in water heaters because I never had one bit of trouble with my old heater...I'd give anything to get that heater back right now :(

    Noticed some soot marks on underside of draft hood to...I gotta take a break from this stuff I guess..I'm trying to do too much at once
    Last edited: Dec 9, 2009
  9. Doherty Plumbing

    Doherty Plumbing Journeyman & Gas Fitter

    Messages:
    810
    Location:
    Penticton, BC
    An electric would probably cost about $250/year or so.

    Well secondary air is the air supplied during combustion to ensure complete combustion. And you aren't getting perfect drafting because if you were you wouldn't get any smells what-so-ever.

    The flames will often burn yellow at the tips of periodically when there is dust in the air etc. If your flames are constantly yellow at the tips you need to do some investigating. You should also not have soot on the draft hood. Soot is often cause by condensing flue gases.

    If you have a manometer you should check the gas pressures across the gas valve. Most HWTs require 7-14" water column on the inlet and put out 3.5" water column to the burner.

    I am really almost certain the goofy venting is playing a roll in this fiasco. For each 90* elbow in the vent connector you need to reduce the vents capacity by 10% so if you have 3 or 4 elbows that's a HUGE reduction in what that vent can take.
  10. vtxdude

    vtxdude New Member

    Messages:
    127
    Location:
    NH
    Thank you for your insight on this..at this point I am thinking of going electric...for whatever reason the Kenmore water heater will not work like the Vanguard I had in there :( I don't have any other way to route my venting...flames are not consistently blue

    I am so ticked that the plumbers who came out here did not say or offer any advice....I know Sears doesn't pay much and it is not worth it to them but we are talking about peoples health and lives here.

    I am going to try to recoup as much as I can from Sears because ultimately they are responsible (imho)


    I am so disappointed
  11. vtxdude

    vtxdude New Member

    Messages:
    127
    Location:
    NH
    I am going to try once last time to get this water heater running smell free......right now the pipes have both adhesive from the foil tape that one of the Sears plumbers left and also the caulking from the fire retardant stuff that was put on


    I'm thinking maybe with brand new pipes with no tapes, caulking , adhesives etc should give me an idea if the smell is coming from the pipes or is the water heater itself no?


    I believe it is drafting correctly...with one of those long butane lighters next to draft hood it is drawing the flame over towards the flue.....


    I was just going to switch to electric but figure I'd give this one last shot




    Oh I know it isn't done that often but can I use Type B vent pipe all the way through from the draft hood all the way up?? Like I said I know it isn't the norm but can it be done?

    Sorry for all the questions, just that i will sleep better knowing I tried this option before going electric



    Thanks
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