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Multilpe Boilers

RobGRobG Member Posts: 1,850
On a multiple boiler install, with pumps on each boiler, does it need to be piped in reverse return?



  • ya asking this

    Ya asking this after you make comment about my expertise on other post, that's explained how much you don't know ..
  • ya asking this

    Ya asking this after you make comment about my expertise on other post, that's explained how much you don't know ..
  • SWEISWEI Member Posts: 7,356
    As usual

    it depends.  Reverse return is best, but a big header pipe with short branches is pretty forgiving.  The important thing in my mind is hydraulic separation.
  • RobGRobG Member Posts: 1,850

    Please use correct grammar. (And only hit the "submit post" button once). I noticed that YOU didn't answer my question, only criticised as usual.
  • i do have grammer

    I do have grammer problem due to my disabilty, you have a problem with that??
  • RobGRobG Member Posts: 1,850
    multiple boilers

    What would be the best way to balance a system with two different sized boilers requiring two different flow rates? Two primary loops with correctly sized pumps and a staged controller to fire the smaller boiler until its capacity exceeds the load, then fire the larger boiler and shut down the smaller until its unable to meet the load, then fire both? The multiple / modular systems I am used to utilize the same size boilers.

    And rjb, what is your disability? Anger management? 

  • Mark EathertonMark Eatherton Member Posts: 5,584
    edited December 2013
    Either Primary secondary or...

    either direct or reverse return, and as others have said, make certain the headers are short and fat.

    If you go parallel reverse ir direct return, you MUST have a check valve on each individual boiler pump.

    If more than 2 units, and one common pump then I usually go reverse return. It is somewhat self balancing if the pressure drops though the units are the same.. If each unit has its own pump and check, and the headers are correctly sized, it shouldn't make that big of a difference if its direct or reverse return.


    Edited: Changed should to shouldn't. Thanks for the catch Kurt.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • JStarJStar Member Posts: 2,668

    Violation of Rule #1. Please stop or avoid posting.
    - Joe Starosielec
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  • Steve WhitbeckSteve Whitbeck Member Posts: 669

    What I do is have one set of closely spaced tee's ( primary / secondary piping )

    but I use the same size branch as the main ( OR big enough to handle the total flow of all boilers ) 

    I then tee off to each boiler. All returns to boilers come off of one branch and all supplies from boilers come off of the other branch.

    Each boiler has it's own pump and piping that should be sized for that boiler.

    This way if the boilers are staged in it won't matter what one is fired first if you have them rotate the lead boiler.
  • Dan HolohanDan Holohan Moderator Posts: 11,877
    I have to agree.

    He's making a good point, Ray. We have a good thing here. Please be nice.
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    Hug your kids.
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