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recirc line

jonny88 Member Posts: 1,139
how do you guys prefer to pipe in a recirc line into a indirect without a designated port.

...into bottom of tank(remove drain and install tee etc) or into cold water supply with check.thanks


  • hot_rod
    hot_rod Member Posts: 22,258
    Do you have a thermostatic mixer on the tank?

    It's a good idea to use a listed three way thermostatic mixer, both from a liability standpoint, and to run the tank at 140F or hotter for anti-legionella protection. Hotter tanks also provide more draw down. Stay below 160F though to extend the tank life and limit mineral precipitation.

    With a recirc and a mixer you need to pay attention to the check valve locations and the cross over piping. If not you may, probably will :) experience temperature creep.

    If the recirc pump runs 24/7 and there is no draw during the evening, eventually the cold port shuts down, as it starts seeing the recirc temperature. Eventually the entire loop, less the heat loss, will be the same as the tank temperature.

    The first DHW draw in the morning will experience tank temperature water until that line is purged and the cold port of the mixer sees cold temperature and can respond. Often the mix valve blamed, but it's a piping snafu.

    A timer and thermostat on the recirc could help eliminate temperature creep also.

    This journal has some excellent piping options and explanations for DHW.

    Pages 49 on talk about recirc piping.


    On large commercial tanks the recirc is sometimes tied in mid port on the tank, not into the cold, dip tube.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • jonny88
    jonny88 Member Posts: 1,139
    thanks rod

    yeah i am using a mixing valve on outlet and storing water at 140. Burnham Alliance doesnt show a piping diagram for a recirc line.I saw on a taco drawing about bringing it into the bottom of indirect.Actually my first time using caleffi material and what quality they have.I will post pics after install.Thanks again.
  • jonny88
    jonny88 Member Posts: 1,139
    re circ line

    I forgot to mention there will be a pump on the recirc line
  • Ironman
    Ironman Member Posts: 7,379

    Gives you a recirc port on their domestic mixing valve. Not sure about other brands.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
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