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Community and Q&A

Logic plumbing layout

dfvellone | Posted in Mechanicals on

I’ve read the article here on zoned trunk and branch plumbing advantages over home run/manifold layout, but have since then read about logic plumbing and its use of multiport tees. At a glance it certainly seems to make sense and would improve on zoned trunk and branch if used in conjunction with that approach. Am I missing something?
Thanks, Daniel

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  1. Jon_R | | #1

    The hybrid approach uses less connections but more tubing.

  2. Expert Member
    AKOS TOTH | | #2

    I've tried this even before it got a name. The issue is the same as most trunk and branch setups. Even a not too long trunk of say 20' of 3/4" pipe before the multi point T, the wait time for hot water is still pretty long. It does work quite well with recirc if the multi point T is close to your fixtures as you can use one ports for recirc return.

    If you want quick hot water and don't want to run a recirc setup, a hot water heater near your loads with home run is still the best.

  3. Expert Member
    BILL WICHERS | | #3

    I think which way you do plumbing depends a lot on the layout of the structure. In some structures, a trunk line will be most efficient. In other structures, a branch type system may work best. Both have advantages and disadvantages, but sometimes one will be much easier to install than the other. It’s important to think of layout and installation labor concerns too.


  4. jberks | | #4

    I'd also like to add the considerations of hot water recirculation. If you're going to incorporate recirc and how that will change which system layout is best suited.

    I was once hellbent on the homerun layout. Then when I was getting closer to installing it, I was thinking about the logistics of physically running all that tubing through floors/walls, the lack of space I had, the hourly cost of my plumbers and quickly running out of my plumbing budget, so I sat down to redesign. I am now hellbent on the multi-manifold layout (or "logic" as uponor calls it)

    If you're going without hot water recirculation, or from an interior design perspective, would like to do wall hung fixtures, and using a central water heater I suggest the logic system. as Akos pointed out, electric point of use heaters are probably the best, however if gas is the preferred heating system, I haven't seen any gas point of use heaters in North America yet (still waiting) so with one central gas heater, I believe the logic layout works well.

    I'm also waiting on better/cheaper PV systems to justify at point electric water heating but that's another conversation

    However, with the the logic layout, if you want hot water recirc (which I did), you will need an individual recirc pump for each hot manifold, I'll note there is another approach I considered, with 1 pump for 4 recirc lines with pressure gauges and ball valves to manually teeter each line, but I felt that was too "jannky" of an approach.

    So in consideration, if you do want a recirc line, and want the simplicity or cost savings of only 1 recric pump, a Gary Klein style trunk & branch loop system would simplify the recirc portion and still be an effective overall system.

    Just my thoughts,


  5. tommay | | #5

    Check your local plumbing codes or talk to a plumber to ensure you have the proper sizing of piping required for the fixtures you have....If it is being inspected, you gotta have it right. If you don't, you may find you have a volume problem down the road if more than one fixture is being used.

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