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I don't have 18"

h12721aah12721aa Member Posts: 17
   I am installing a new boiler and have some problems with dimension.


 1 1/2" piping coming from the boiler system supply in to the Air Scoop. there should be 18" of horizontal pipe witch i don't have.


 Between  the supply and the return I should put a  1 1/2" by pass valve. With two Ts and the valve I don't know if that will fit in 5". Must the By Pass Pipe also 1 1/2" or can I go smaller ? The boiler is a Burnham MPO-IQ 84 for two Zone and water heater.

The print shows 1 1/2" pipe lay out.

What to do? going around in loops or what ?



  • Rich_49Rich_49 Member Posts: 2,540
    edited August 2014
    Air scoop or eliminator

      The 18" rule is a good one to be thinking of but not so important if you have a modern air eliminator as opposed to old style air scoop . Which do you have there ? Send a picture or 2 .
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
  • hot_rodhot_rod Member Posts: 13,182
    what size boiler?

    If that is a 64,000 BTU/ hr hot water boiler you could use much smaller pipe, check with the installation manual but 1" pipe should easily move 6 gpm or so.

    1-1/2" pipe needs around 11 gpm flow rate to assure 2 feet per second. You want 2-4 fps to be able to push or pull the air around the piping loop.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • h12721aah12721aa Member Posts: 17
    edited September 2014
    I don't have 18

    Hi Rich and hot rod

    This is a reply to the question. I don"t have a picture of the air scoop look at the print.

    A Table calls for a flow rate of 4.5  Gal/Min for the MPO-IQ84  = 64000BTU.

  • Paul48Paul48 Member Posts: 4,492
    Pipe Sizing

    One inch is fine for 4-9 gpm. A spiro-vent has none of those piping restrictions.
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