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

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?

Comments

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,935
    edited November 2022
    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 HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • virtualplumber
    virtualplumber Member Posts: 35
    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: 18,195
    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
    I added a drawing of the actual layout below.
  • virtualplumber
    virtualplumber Member Posts: 35
    Will this work?
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,935
    edited November 2022
    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 HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • virtualplumber
    virtualplumber Member Posts: 35
    edited November 2022

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