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new water heater venting question

I'm getting my water heater replaced. i was told the hood and vent used on my unit now was small for it(3 inches).
I have a chimney with liner installed. If new heater requires 4 inch vent and the opening to my chimney is 3, will installer adjust that? is that something that is common?

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 23,168
    Ah... depends on the chimney liner itself (not the opening in the chimney). If the chimney liner is correct as to type and size, then the installer can adjust the connections.

    If it isn't... you have a big problem.

    You should verify the type and size of the liner in the chimney -- you may need to have a chimney sweep to do that -- before proceeding.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • sonicboomin
    sonicboomin Member Posts: 11
    thanks for reply. not sure to be honest, chimney not used as fireplace as we dont have any, runs from center of house from basement to roof.
    i have steam boiler and water heater connected to it from basement.
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,506
    You have both a steam boiler and a water heater connected into a 3" liner?
    steve
    SuperTech
  • JUGHNE
    JUGHNE Member Posts: 11,042
    I would guess he has a masonry chimney with a liner that is large enough now for the boiler and WH. Old WH has 3" vent, new might have 4" vent, 3" is maybe WYEd into liner......or liner is old school masonry with only a 3" hole in it.
    SuperTech
  • sonicboomin
    sonicboomin Member Posts: 11
    Hi no, opening for steam boiler is much larger than 3 inches.
  • JUGHNE
    JUGHNE Member Posts: 11,042
    A picture showing the whole set up would clear this up.
  • sonicboomin
    sonicboomin Member Posts: 11
    i will take pic once im home. FYI new boiler is AO smith 50 gallon 40000 btu,
    anyone know if 3 inches will work for that model?
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,453
    @sonicboomin

    Flue pipes and liners are sized for each individual job. They are base on btu input of water heater, btu input of steam boiler and height of chimney and type and size of the existing liner

    We would need all the information to do that, but that is up to your installer. 3" flue may be fine for the water heater
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,273
    Hi, I’d like to see the spec sheet for the heater. Normally 3” vent is fine for 40,000 btus.

    Yours, Larry
    kcopp
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,453
    I could be wrong but I think a natural draft water heater that normally can use a 3" vent has to be 4" under some conditions I think if vented with a draft assisted boiler
  • JUGHNE
    JUGHNE Member Posts: 11,042
    Pictures??