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Low Temperature mixed side radiant injection pump issue

rosy Member Posts: 9
This ? concerns a mixed lower temperature zone that I had planned to use a Tekmar 722 w/ motorized actuator and Tekmar 363 control. On the advice of a very knowledgable radiant specialist who posts here regularly, I am scrapping the 722 four way valve and switching the plan to a Grundfos 15/42 injection pump run ostensibly by the 363 (which it originally did years ago). Piping is 1.25" copper, horizontal "U"with 3/4" for the injection piping through CST's.
Question is this. Rather than use the 15/42 and Tek 363, I was wondering about using a Grundfos Delta T Miximizer or a TACO VT 2218 Delta T pump, which is about the same size but is programmable to run the temperature where one wants it. Besides the facts that this very knowledgable specialist advised against it, and I do have both the 363 (which has outdoor reset) and the 15/42, HAS ANYONE OUT THERE HAD ENOUGH EXPERIENCE WITH EITHER OF THESE PUMPS SUCH THAT THEY FEEL COMFORTABLE ADVISING ON THEIR DURABILITY AND EASE OF USE?


  • hot_rod
    hot_rod Member Posts: 22,259
    With injection mixing you need two circulators, the injection, and system circs.
    The Taco I Series valve seems to be a popular solution for mixing valves with ODR. Then you could use the ECM circ of your choice.

    Injection mixing with circs is not so common these days.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream