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Layout Design Feedback

CWalker
CWalker Member Posts: 2
in Radiant Heating
Boiler Test.jpg

Looking for some feedback on this layout. We had a full system replacement but wanted to keep the original cast iron radiators in the house to maintain the history (also we do kinda love em). We did go for an in floor heat option for areas with tile, we also went ahead and added some modine unit heaters in the basement as we utilize the space year round as a shop. There was also an additional zone added for an area that had been built on that was using an under cabinet heater, we also wanted to leave space to add additional ones in the future. We went ahead and did home runs from zoned manifolds to everything. In terms of BTU and sizing we are comfortable but want to make sure as we throw equipment on the board we dont miss anything.

Equipment planned:

NTS FTVN Boiler

Caleffi manifolds 668S1 with purge valve and auto air vents

Taco 4 zone valve control panel with priority

Taco sentry zone valves

Taco thermostatic mixing valve

Taco 0013 Variable Speed Delta-T Cast Iron Pump

Ideally we want to keep it as simple as possible and need to move as quick as possible given the time of year! Any input is greatly appreciated.

Comments

  • Derheatmeister
    Derheatmeister Member Posts: 1,659
    edited September 14

    Sounds like the system is being layed out as a two temp system..

    While this is great the piping techniques on the low temperature side should be Changed/rearranged

    We would install a additional circulating pump based on the required flow

    This Circ would be "upstream" from the Mixing valve (Mixed temp side)

    This "low temperature Branch" would be via Closely spaced (Primary/Secondary) Tees preferably Downstream from the high temp rads.(Return to Boiler).

    Hope this helps.

    Edit: The expansion tank and fill should also be on the point of no pressure change which is perferably prior to the circ. (Inlet)

  • psb75
    psb75 Member Posts: 1,067

    I think Derheatmeister mean't "downstream from the Mixing valve" (Mixed temp side)— i.e. pulling from the mixing valve. Respectfully.

    Derheatmeister
  • Kaos
    Kaos Member Posts: 712

    I would look at the install manual. It shows two common ways of piping this up. If your smallest zone's flowrate is around 2GM, you can go direct to load (kindof what you have sketched, but the pump is built in so you don't need an external one).

    image.png

    If your zones are smaller, you can go with primary secondary piping. Unless you a very large system, the 0011 is overkill.

    image.png

    In either case, as others have said, you need a separate pump after the mix valve for the low temp zone.

  • hot_rod
    hot_rod Member Posts: 25,649
    edited September 14

    Here is a piping option that I have used.

    It uses a manual 3 way mix valve with a proportional reset logic.

    Screenshot 2025-09-14 at 7.58.05 AM.png

    Basically the boiler runs on outdoor reset control, adjusting to the temperature needed for the radiators.

    The radiant is fed through a basic tekmar 3 way mix valve. It's output temperature floats along with the boiler temperature adjusted by ODR

    I believe that boiler has a pump inside? Check the manual online.

    I would use a delta P, pressure regulated, circulator on the zone valves, and also on the radiant manifold if it is zoned?

    Radiators could have TRV individual controls also.

    Attached is a page from the NTI manual showing primary secondary piping.

    Piping showing TRVs on radiators

    A sketch with the 3 way

    Water quality page

    Details on proportional reset control from Idronics 4

    I'm partial to Caleffi components :) but what you describe will work;

    Screenshot 2025-09-14 at 7.29.49 AM.png Screenshot 2025-09-14 at 7.36.56 AM.png Screenshot 2025-09-14 at 7.40.17 AM.png Screenshot 2025-09-14 at 7.47.11 AM.png Screenshot 2025-09-14 at 7.28.59 AM.png
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    PC7060

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