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There’s a nasty smell when the gas boiler is on

maroo Member Posts: 29
edited April 4 in Gas Heating
I’ve noticed the past few days that I’ve had the boiler on that there is a nasty smell and it isn’t coming from the room where the boiler is but it’s coming from the kitchen and the stairs and hallway near the kitchen. It doesn’t smell like rotten eggs. It only seems to stink at night time and some days it smells like animal feces and sometimes it smells like cat litter. We don’t own any pets. I called the gas company about a week ago and supposedly he checked for gas leaks and said he didn’t find any but there were three gas leaks here about two years ago so I’m always paranoid. I don’t know why this smell keeps occurring and it was really strong the other day to the point where my child kept coughing. Does anyone know what this could be?  And I forgot to add that the smell goes away when I turn the boiler off. That’s why I suspect that it is the boiler. 


  • kcopp
    kcopp Member Posts: 3,996
    What type of heat registers do you have?
    It could be a dead mouse in one of them
  • Jamie Hall
    Jamie Hall Member Posts: 19,139
    Sounds a lot more like a dead critter getting warmed up by the boiler than it does like gas -- gas is a pretty distinctive smell.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    JUGHNE Member Posts: 9,821
    Do you have a floor drain or washer standpipe in the basement?
    If the traps dry up then sewer gas is possible, just pour water in them to eliminate that candidate.

    When the boiler is on it is causing air currents in the basement that you may not notice. And a little smell can travel a long ways.

    As Jamie said, you could be cooking a critter in the boiler, exhaust pipe or chimney.
  • mattmia2
    mattmia2 Member Posts: 5,730
    I suspect it is pulling combustion air our of the sewer either through a dried out/broken trap or an open pipe somewhere or a failed air admittance valve.