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Piping question (SE)

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Brad White
Brad White Member Posts: 2,398
If I have this right, Steve, I can see a one-pipe setup as a retrofit to an existing Monoflow system with a single system-side circulator. One main out and back.

Each branch would perform as it always had (with continual main temperature dilution), but in the end, the total system-side delta-T would be the same.

The advantage I see (assuming the system flow at least equals or exceeds the boiler flow) is that the return water going back to the boiler will be the coolest return water you have.

Now, if you are thinking that it is one continuous loop out around and back, with branches feeding out via circulators, then I agree with you, it is a head-scratcher.

Without a main secondary circulator, each pair of tees would draw what it wanted and would be as likely to recirculate and dilute rather than complete the circuit. The low loss header would disallow an effect from one to the other except gravity flow if that.

Only if that loop were divided mid-way (making it 2-pipe) and the return branches on the return side, would that work effectively. But then, it is no longer a one-pipe, is it?

Can you post the diagram or recreate it to be posted?
"If you do not know the answer, say, "I do not know the answer", and you will be correct!"



-Ernie White, my Dad

Comments

  • Steve Ebels_3
    Steve Ebels_3 Member Posts: 1,291
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    Piping topic for the day

    Is there any circumstance, hydraulically speaking, where a single pipe primary secondary approach would be an advantage on the system side of a low loss header/hydraulic separator?

    This piping layout was shown in a manufacturers application manual and I can't see any reason for it whatsoever. It makes the addition of a "system" circulator mandatory when from what I can see, the zones circs will each do their task without it just fine. It will also reduce the available water temperature as each zone dumps back in to the primary loop. It's got me puzzled. What am I missing?
  • hot_rod
    hot_rod Member Posts: 22,143
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    I'm not sure

    exactly what you are describing? Got a drawing? Single pipe P/S??

    hot rod
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Steve Ebels_3
    Steve Ebels_3 Member Posts: 1,291
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    Single pipe

    As in just a single pipe loop. A circle if you will as opposed to two pipe P/S, like the rungs and sides on a ladder which supplies the same water temp to all zones.

    I had all those drawings saved on my computer but it crashed and burned.
  • hot_rod
    hot_rod Member Posts: 22,143
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    Sounds like they

    may not understand, or believe the concept of the hydro-separator?
    Adding another P/S loop would complicate the calculations on actual water temperatures getting to the zones, as you have two blend points to deal with. As I see it.

    hot rod
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Brad White
    Brad White Member Posts: 2,398
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    Steve

    From what you say, as a loop, the portion that makes it a loop (across the rungs) defeats the purpose and defeats differential pressure across the rungs.

    If it is a rung system then the dilution factor (if in-series S/R-S/R tees) no longer is a concern.

    Maybe it is a diagrammatic drafting error? Maybe that part should be a pressure differential valve? I really do not know unless I see it.

    With a hydraulic separator it would need it's own circulator of course.

    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"



    -Ernie White, my Dad
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