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Oil to gas boiler conversion smell


We recently converted our old oil boiler to gas with a Carlin G3B.
Boiler is a Utica model no.500
1 pipe steam system to 10 radiators
House is an old brownstone so a narrow home basement then 5 floors to the roof.

It was just converted yesterday and there's been an exhaust like smell. It seemed more strongly at the radiators and my bedroom on the first floor. The basement where the boiler is doesn't really smell like it. First day it burned my nose a bit.

We put in a new CO detectors and they haven't made any noise.

I tried to do a bit of skimming but I maybe didn't do as much as is necessary. I filled a small 2 gallon waste basket a few times. First time some black water came out and then ran clear and after that another few clear "skims". I think the smell got better definitely not as bad as the first day.

I know the plumber had the wrong nozzle on the g3b as it was for propane but guess he just drilled it through to get it working.

My question is how would I know if the smell is exhaust/chimney issue vs some leftover oil from pipe fittings etc. I get used to the smell and notice it less when in the house but if I'm gone for a few hours I'll notice it when I come home.

It's only been a day but want to know what I should keep my eye/nose out for.

Should I keep skimming maybe using some 5 gallon buckets?



    EBEBRATT-Ed Member Posts: 15,512
    Did the plumber do a combustion test with instruments? Was the chimney checked?

    I don't understand the skimming if the boiler was existing.

    I would be very cautious of carbon monoxide & flue gas.

    Don't become a statistic
    HVACNUT Member Posts: 5,828
    He probably didn't touch the water side at all if it was a conversion. 
    Are you saying the burner came with a propane orifice, so he drilled it for natural gas to the correct size for the BTU input for the boiler?
    Can you post some pics?
    Was a chimney liner needed and installed?
    Was a gas draft regulator installed, with a safety spill switch?
    Was the boiler brushed and vacuumed beforehand?
    A combustion test is a must. 
    You shouldn't be smelling anything from the boiler. 
  • Jamie Hall
    Jamie Hall Member Posts: 23,273
    The exhaust from either LP or natural gas combustion has a remarkably distinct, rather sharp odour -- which is characteristic. Describing odours is not my thing, but once you've smelled it it's unmistakable. Do have someone check the entire installation as noted above.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England