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Distance from chimmney to boiler?

Nick Z._2
Nick Z._2 Member Posts: 32
I have a custmer who wants to put her boiler 10' from the chimmney.I told her no way, I would like to be able totell ehr what the max. is by code.
Thanks Nick


  • Mad Dog
    Mad Dog Member Posts: 2,595
    Nick, there are no rules of thumb here

    many variables come in to play: boiler's btu input, distance to chimney, pitch, developed length of flue pipe, type of flue pipe, type and height of chimney, et cetera. Generally speaking you are correct in you innate feelings, that is usually too far. ALL new boilers come with Instructions which usually will tell you all of this. However, if you are going to be doing this for a living PLEASE get your own copy of THE NATIONAL FUEL GAS CODE, N.F.P.A. 54 AND USE IT EVERY TIME. I know its easier to just ask someone (we all have done that) but this is probably the MOST important aspect of safety in our trade! Spillage of flue gas and CARBON MONOXIDE need to be manhandled and very actively - no pussy-footing here. If you can get us all those details, we will try to give you a safe distance. Regards, Mad Dog

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  • Jim Davis
    Jim Davis Member Posts: 305
    Horizontal length

    Their actually are some guidelines for horizontal runs in the venting tables. In most cases with single appliances the horizontal run cannot be longer than the vertical height. If a chimney is 30' tall, 30' horizontal is acceptable in most flue sizes above 6". The question is not how long it is, but does it work. 10'horizontal is totally acceptable in the charts if the chimney is taller than 10'.
  • Dale
    Dale Member Posts: 1,317

    As another post said a copy of the fuel gas code is a good investment. With that you can correctly design vent for any catagory 1 applaince. 10 feet with correct slope is usually no problem, if gas using b vent is always a good idea and can increase max distance. Most distributors offer venting classes a very worth while 4 hours in my opinion.
  • Weezbo
    Weezbo Member Posts: 6,232
    Many variables...........

    Is it gas, oil, wood ....?
    There are lots of codes.
    Induced draft?
    this isnt a code however, 1/3 of overall developed length of stack = maximum horizontial Graded run. you could say it was a Standard used in the trade ,and yet not mention it was my standard:) dont forget 90s need to be "factored"into the calculation. now the home owner will leave you alone and you can move the boiler over where you want it to be:) Happy Boilering:)
  • Jack_23
    Jack_23 Member Posts: 153
    NFPA 54

    says that on a gas fired Cat I appliance you can have a vent connector 1.5'/in diameter of appliance breaching. So a 4" vent connecor can have 6' of single wall vent pipe.

    As far as oil goes, 31 does not address venting in as great detail as 54. There are no vent tables in the 31 code. Appendix E is just an appendixz an not a part of the code.

    Your idea to limit the length of the vent connector is, IMHO, correct. If yoou must run a long vent connector, use insulated pipe. Dura-vent (DVL), Selkirk (DS) and AirJet make double wall L vent that is great for vent connectors for oil. I have used 4" pellet vent (it is L vent and approved for oil) for both vent connectors and relining systems. You can reduce the vent pipe diameter with manuf spproval...in writing!
  • Firedragon_4
    Firedragon_4 Member Posts: 1,436
    NFPA 211 is the standard

    for oil and solid fuels.
  • jim lockard
    jim lockard Member Posts: 1,059
    What does

    The boiler manufactor say ?
This discussion has been closed.