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New boiler sewage smell

angdell120angdell120 Posts: 28Member
edited March 2019 in Gas Heating
We got a new boiler installed a month ago(x-2 series boiler) Every time it is on the basement stinks like sewage the company we used has no answers as to what is happening. One day after the install the boiler blew about 3 gallons of water on the floor. They said the PSI must have been too high. We just don’t know where to begin, any suggestions?


  • Jamie HallJamie Hall Posts: 12,132Member
    Hot water or steam? "The company said the PSI must have been too high". Indeed, if the relief valve opened. And there is no excuse for that -- getting the pressure right is part of the install, and if they didn't get that right one has to wonder what else they messed up.

    A sewage smell is not common from a boiler -- but if there is inadequate combustion air coming from anywhere else, and there is a dry trap in a floor drain (not at all unusual!) that would do it.

    Where to begin? Find a competent contractor. Where are you located? We may know someone...
    Br. Jamie, osb

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • DZoroDZoro Posts: 1,020Member
    post some pics of the install and boiler room.
  • angdell120angdell120 Posts: 28Member
    We are in New Britain, CT
  • angdell120angdell120 Posts: 28Member
  • JUGHNEJUGHNE Posts: 6,532Member
    Simplest guess is that when the burner fires the draft out the chimney is trying to pull air out of the basement.
    It could be pulling sewer gas out of either an open or loosely sealed pipe fitting or floor drain or washer drain which have dried up traps.
    How well are the sewer drain pipes to the right of the boiler sealed up?
  • JUGHNEJUGHNE Posts: 6,532Member
    For the relief valve opening problem, can you show us the expansion tank. Maybe an old one hanging up between the ceiling rafters. Show more piping above the boiler also, especially where the new connects to old pipes.
    Do you have cast iron radiators?
  • angdell120angdell120 Posts: 28Member
    We think ok, we don’t have any leaks. We don’t have any floor drains and the washing machines drains into a slop sink and no smell coming from that drain.
  • JUGHNEJUGHNE Posts: 6,532Member
    Drain lines can have something open that will not leak water out.
    Just that sewer gas can be pulled out when the boiler fires.

    You could open a window and see if the smell persists with free flowing combustion air coming into the basement.
  • EBEBRATT-EdEBEBRATT-Ed Posts: 6,556Member
    Cold be the "new boiler burning off smell" We seem to get a lot of those lately.

    We installed a Peerless oil fired this winter for the secretary where I work. She went crazy for 3-4 days while it burned off. Kept the windows open while she was home. Finally disapated
  • DZoroDZoro Posts: 1,020Member
    Closely inspect the cast iron drain pipes for cracks. Looks like there was a pipe going up from the cast with a poorly fitted cap. Check that cap, looks like it might be the wrong size for the pipe. The pipe looks like it might be copper and a iron size cap was used for it.
    Also does the slop sink have a drain trap under it?
  • angdell120angdell120 Posts: 28Member
    silly question, should we call a plumber to check out that cast iron pipe?

  • ratioratio Posts: 2,213Member
    The last bad boiler smell turned out to be a squirrel crisp on top of the boiler block, IIRC. If you can stand it, see if it's stronger in any one place in the basement.
  • angdell120angdell120 Posts: 28Member
    Within 24 hrs it started to smell, I don’t think an animal got in that quickly.
  • Intplm.Intplm. Posts: 1,047Member

    silly question, should we call a plumber to check out that cast iron pipe?

    Within 24 hrs it started to smell, I don’t think an animal got in that quickly.

    Animals can get in that quickly. So don't dismiss that possibility too quickly.

    @angdell120 Does the smell, smell like it is low tide near the rocks at Hammonasset? Then it is probably the drain pipes behind and to the right of the boiler. A few things do not look correct there. The rubber fittings, or fernco fittings that are installed on the cast iron drain pipes might need to be looked at. From the picture I can see that the drain plug clean out is against code.
    Do have the plumber come back. Have them look for the cause of the smell and install a proper clean out plug. That plug might be that cause of the smell.
  • ZmanZman Posts: 5,532Member
    Check the rubber "furnco's" on the sewer pipe in the against the wall. Does the room have a floor drain? Is it full of water?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • EBEBRATT-EdEBEBRATT-Ed Posts: 6,556Member
    Start with the simple things first
  • HVACNUTHVACNUT Posts: 2,857Member
    That furnco cap looks like something I'd use to pump down the old boiler and purge zones.
    The force of the water from the pony pump could've opened a sweat joint. DWV copper?
    I would cut it below the tee and put a new furnco cap on.
  • angdell120angdell120 Posts: 28Member
    Thank you everyone, we have another plumber coming this week to check out the drain pipe & furnco. Hopefully get the smell of Hammonasset out of my house! 😣
  • Intplm.Intplm. Posts: 1,047Member
    Good luck @angdell120 please let use know how things turn out.
  • Erin Holohan HaskellErin Holohan Haskell Posts: 1,221Member, Moderator, Administrator
    Any updates, @angdell120 ?
  • plumbdevplumbdev Posts: 1Member
    Where is the low water cutoff?, expansion/compression tank? If the system has a lot of volume where is the bypass? is there condensation while firing?The water supply valve to the boiler is left on to the auto feed. Auto feed can over pressurize causing the relief to blow. Was there or is a there a leak in the system? did the contractor use stop leak to fix? If so, the stink can be from the relief of boiler water with stop leak in it.
  • meticulousmikemeticulousmike Posts: 28Member
    where is the expansion tank,air scoop and vent combo on the supply side on the boiler?why is the supply plumbed into the return and why isn't there a shutoff after the pressure reducing valve aka boiler fill valve?they should always be left in the auto fill position(lever down)..i always plumb the fill valve supply below a 90 as far down as i can with a shutoff below that where the tee goes into the pipe and plumb the scoop,tank,vent combo as far as it can fit on a horizontal pipe on the supply side leaving the boiler-this way when cold water is filling the boiler for the first time it has time to separate the air from the water by hitting that 90 and have time rising to the top of the pipe before the scoop takes over also when it's fully heated it separates even more to be vented out.
    drain cleaning, plumbing,heating and electrical repairs.
  • HotanCoolHotanCool Posts: 53Member
    Old house, old chimney! You sure it's a sewage smell? And they could have pipe differently to have more room on the left. But it's always about money.
  • psb75psb75 Posts: 155Member
    The black cast iron sewer pipe is too prominent a feature in your pictures to ignore as a possible source of the smell. And there are enough vagaries in the small sample we see that the rest of it may be suspect. Have it thoroughly inspected. The OTHER suspect is the SMALL black cast iron pipe in the picture--the gas supply pipe. Make sure that is checked out TOO. Leaking natural gas is scented to smell like methane--as a warning.
  • Charlie from wmassCharlie from wmass Posts: 4,111Member
    Can a photo of the washing machine drain get posted along with any other drains in the basement?
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • JackmartinJackmartin Posts: 142Member
    Okay firstly ,how did your installer get away with not installing a combustion make up for your boiler? This would not pass inspection in Canada. Your basement is so closely sealed that you are pulling sewer vent air into your living space and believe me that is not good for your health. Open a window and fire your appliance if the smell is not present than you know the boiler requires it’s own combustion air ,any appliance needs oxygen to burn and it will cause a negative in the room if this is not provided. I am looking at your pictures and I have to ask a silly question ,does this actually heat your home? The connections to your boiler are the smallest I have ever seen in this size of boiler. Where is the expansion tank and why did they mount your pump where it is impossible to service? Tell me did you get a tap and toilet plumber to install this boiler it certainly looks like it ,no experienced heating contractor would do an installation this way ,it is impossible to service. Once again the brains you had install this boiler put the pump on the wrong side ,tell us the company name and I will send him a copy of Pumping Away so maybe next time he can get it right I am so sick of looking at lousy work I will send it free, of course that being dependent on his attitude, if he thinks he knows everything there is really no point. One last comment and this is directed to your gas inspectors, do they really let gas piping go with no swing joints or combustion test after the appliance is installed? In the event your screwup had done a combustion test as he is supposed to ,he would have immediately seen the problem from his combustion analyizer. I hope the plumber you are contacting has the correct equipment to do your problem solving correctly, walking around and using your nose is just stupid. All the best Jack Winnipeg Canada
  • angdell120angdell120 Posts: 28Member
    Hello everyone, I am back months later with the issues back again. We just has another plumbing co smoke our lines. No leaks but the sewage smell has come back with the cold nights..... seems like no end in sight. Can anyone recommend a plumber in the Hartford CT area who can help us?
  • JUGHNEJUGHNE Posts: 6,532Member
    FWIW, just a couple of long shots here;
    It was not uncommon to vent sewer lines into chimneys years ago, (one less hole in the roof, connected sewer vent in the attic into the chimney). Cold down draft could pull sewer gas down until boiler fired. If your old boiler has a standing pilot light it may have kept the chimney warm enough to maintain gravity flow upward.
    You should see at least one sewer/drain vent pipe thru your roof.
    How close is it to your chimney?

    Or you could have a loose lead joint in the CI piping. Water would not leak out as the flow is into the hubs. Smoke may have went out thru the roof vent if there is one. The lead can possibly be re-tamped if loose.
    Was the boiler firing with all doors and windows closed when the smoke test was done? And was the sewer roof vent plugged for the smoke test?
  • MikeL_2MikeL_2 Posts: 220Member
    I suggest opening the nearest soil pipe when the odor is present to see if the smells match, or perform a peppermint test...........
  • Alan WelchAlan Welch Posts: 192Member
    Did they pull a permit, perform combustion testing, have an inspection done to make sure all code requirements done? looks like they re -used the horizontal flue pipe into the chimney. might be a chimney blockage. Do you have a carbon monoxide detector?
  • FredFred Posts: 8,278Member
    Are you sure you don't have squirrels or some other animal nesting in that flue pipe or chimney and they get asphyxiated and when the boiler fires they get roasted?
  • angdell120angdell120 Posts: 28Member
    @fred, yes we are sure no animals. It happens when the temp drops at night even if the boiler doesn’t go on.
  • angdell120angdell120 Posts: 28Member
    @JUGHNE, you bring up a good point with the oldboiler pilot light. I don’t have a picture of the old one but it was from the 1970’s and the pilot light was visible at all times. This new one you can’t see one if it’s not running. Also it makes these switching noises before it lights. The old one just made this scary noise like the furnace in Home Alone! I attached a picture of the roof...
  • angdell120angdell120 Posts: 28Member
    @alan Welch I am not sure about the permit.... yes we do have carbon monoxide detectors
  • Charlie from wmassCharlie from wmass Posts: 4,111Member
    What else is present in the the basement for plumbing drains? Is there a chimney liner? Has the chimney been inspected with a camera to see if there are any egresses between the boiler and the top that could be sewer vents? Which chimney in the photo services the boiler? Where do you smell the odor the most when it occurs?
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • DocfletcherDocfletcher Posts: 475Member
    2nd most common source of a sewer smell is from a trap whose water barrier has dried out. Make sure you have a proper P trap on the slop sink. Is there a bathroom in the basement?
  • JUGHNEJUGHNE Posts: 6,532Member
    The two center roof ridge chimneys could be checked for bootleg sewer venting by going into the attic.
    Which one of these 3 do the boiler?
    How about a gas water heater, how is that vented?
  • FredFred Posts: 8,278Member
    Are you on a city sewer system or a septic system? If a septic system, when is the last time it was emptied? It is possible waste is slow draining out of the main waste pipe and the odors are backing out of dry floor drains. Is it during evening hours that the family showers, uses the bathrooms more than during the day? Are there floor drains in the basement that rarely if ever get used? They could be dry allowing sewer gases to back into the basement. If you smell it even when the boiler isn't running, the source is likely not the boiler. It just may be coincidental that the odors started around the same time the new boiler was installed.
  • Charlie from wmassCharlie from wmass Posts: 4,111Member
    edited September 2019
    It is highly unlikely to be septic tank in Hartford
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
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