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Would this primary / secondary setup be viable if all 4 zone circ pumps were first in the loop?

Synway Member Posts: 48
edited May 2020 in Radiant Heating
Would this primary / secondary setup be viable if all 4 zone circ pumps were first in the loop with the 4 returns to follow? The actual setup alternates from supply and returns. I am planing on discussing with the owner of the plumbing / heating company tomorrow saying I would like this format with manifolds From the IBC DC Series boiler manual.


  • HomerJSmith
    HomerJSmith Member Posts: 2,407
    edited May 2020
    1" headers are ok, but I prefer ample headers and would have went with 1-1/4". I would also have gone with a primary-secondary piping setup which is what your manual shows. Your boiler pump is in series with the zone pumps, there's not any hydrolic separation. You could throw in a Caleffi Hydrolink or a primary-secondary sys with closely spaced tees to correct your setup.

    I don't believe your sys is piped correctly, but what'a I know.

    I would have used balancing valve to set the flow thru each circuit, since you didn't use a manifold with built in flow gauges. But, maybe the pumps are sized correctly to the circuit resistance to give you the required flow. Hmmm, I doubt it.
  • Synway
    Synway Member Posts: 48
    Yep I called the manufacturer’s tech support and this setup is correct having supply -return ( s-r-s-r-s-r) .
  • Zman
    Zman Member Posts: 7,553
    Manufactures reps work on commission. They will NEVER disagree with the contractor. Your setup is OK with them because the boiler is getting adequate flow. They do not know (or care) about the distribution side.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Synway
    Synway Member Posts: 48
    @Zman thanks again , your comments are appreciated cheers
  • hot_rod
    hot_rod Member Posts: 21,895
    Its there a circulator inside that boiler? The piping layout from the manual indicates a circ inside?

    This is how the early P/S systems were piped with cast boilers. The boiler is within the primary loop, zones are secondaries.

    The first set of tees to the left will get the hottest supply, depending secondaries will get cooler SWT as the returns been in. If that matters?

    If not a circ inside the boiler, I doubt you will get much if any flow if in fact the zone circ and return are primary secondary. There is no means for flow to move thru the boiler.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • HomerJSmith
    HomerJSmith Member Posts: 2,407
    edited May 2020
    I was wrong. In a sense, there is hydrolic separation with the closely space pump tees on the boiler circuit. Hydrolic separation is important.

    The installation parts manual exploded diagram shows a boiler pump in the unit.

    To me the boiler loop is backward on your sys. What "hot_rod" said is true, each zone is going to get less hot water with the farthest zone being the coolest. Each pump should get the same temp of water, but it may not matter because they are so close together.

    Go for it, most probably not all zones will be operating at the same time.
  • Synway
    Synway Member Posts: 48
    @hot_rod yes there is a polymer coated impeller pump I believe
    This is how the early P/S systems were piped
    Yes To the whole here That you mentioned
    Pretty much exactly of your diagram
    So now he says the manifold is too expensive because of the rest of the equipment needed for it.
    He repeated the same concept as manufacturer’s , boiler is modulated eventually the zones get comfortable and controllable by the thermostats and it does that exterior north side of the house sensor adjustment.

    Seems like it is fool proof B/

    So the conversation ended with me responsible for a heat mass (8x10x 3.5” insulated slab) pouring (getting poured) Or putting 27 ‘ of slant fin. More exterior door panels ( 1.6” foam with steal sheath) will be added to the interior basement walls.
    Thanks for all the contributions to my posts