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How should I add a low temp in floor loop to a 180º manifold system.

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virtualplumber
virtualplumber Member Posts: 35
in Radiant Heating
I have a 4-zone manifold that serves a baseboard system. I want to add two new in-floor loops that will need to run at low temps. The current system is not a primary loop design. It is a simple 4-zone manifold with return lines on each zone. How do I temper the new zone?

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  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,852
    edited November 2022
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    Small radiant loop, You will need to add a circulator pump for the radiant loop and a mixing valve. Inexpensive taco 007 pump is fine for this.


    If you are zoning with circulators the piping diagram is similar.

    You may need to add a circulator relay, or get the circulator with the relay built in.


    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • virtualplumber
    virtualplumber Member Posts: 35
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    Thanks for this. I was hoping that I did not have to create a primary loop. What mixing valve would you recommend? Will the second loop ever be isolated from the expansion tank creating an issue? If so should I add a second expansion tank to the new loop? I want to add two small radiant loops. One for a mud room and the other for a small bath. I will use two zone valves for these. Should I use the Taco with the relay? If so will I need a separate transformer for the zone valves?
  • hot_rod
    hot_rod Member Posts: 22,158
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    Other options , so you don't series pumps :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • virtualplumber
    virtualplumber Member Posts: 35
    edited November 2022
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    I added a drawing of the actual layout below.
  • virtualplumber
    virtualplumber Member Posts: 35
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    Will this work?
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,852
    edited November 2022
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    This will work better. if you are showing the 2 blue tubes are return from the floor only. By placing the low temperature returns closer to the mixing valve C inlet, you will get better low temperature control.



    are there 2 low temperature zones?
    That means 2 zone valves and 2 thermostats and something to operate the low temperature pump.

    if both loops can be on the same zone, then all you need is the pump.

    I have had success with the AM101U mixing valve from Honeywell. try this one https://www.supplyhouse.com/Resideo-Braukmann-AM100-US-1LF-1-2-Lead-Free-Union-Sweat-Mixing-Valve-70-145F
    Also available in union PEX and Union FPT

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • virtualplumber
    virtualplumber Member Posts: 35
    edited November 2022
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    Will this work?
  • virtualplumber
    virtualplumber Member Posts: 35
    edited November 2022
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