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Dual temp piping

icy78 Member Posts: 404
Basic question here.
(See pic)
On this type of system, is this a typical setup,  or how could it be improved? For instance, can the in-floor loop have ODR in someway?
The boiler could of course but is the in-floor stuck with 100 degree water (per 3-way setpoint) as long as the boiler buddy storage is above that point?


  • hot_rod
    hot_rod Member Posts: 22,505
    What type of boiler are you running? What is the lowest temperature the fan coil can run and supply adequate BTUs?
    I like 2 or 3 pipe buffers.
    That tank really lends itself to a 3 pipe, like this.
    The Taco I-mix valves are popular for adding ODR to a zone.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    How are you controlling the temperature the the buffer tank?
    Easiest may be you can switch the 3 way to a motorized 3 way control with outdoor reset.
    Second way could be switch to a 4 way motorized mixing valve with ODR.

    There was an error rendering this rich post.

  • icy78
    icy78 Member Posts: 404
    Thanks guys.
    This is a co-workers future project. Since I love to read on this site ,I thought it a great chance for me to learn and  for him to get a decent system.
    There has been no sizing done  yet. ( I posted this while waiting for parts to arrive for my next service call)🙂
    I did tell him to get as large a FC as he could to try to take advantage of a modcon.
    He guessed at an 80k WM Evergreen unit.
    Infloor is for a 30 x 40 once-upon a time pool room, now filled and will get 4" concrete. Lots of windows. Rest of capacity goes to FC for house.
    That's about all I know.
    I stressed the importance of a good heatloss calc.