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To ECM or Not ECM

CurtT Member Posts: 7
edited December 2023 in THE MAIN WALL
Single zone at this time through fan coil with provisions on the secondary loop for additional emitter zones with Zone Valves. Single Grundfos circulator (3 spd) very little head loss at this time and no more than 5 gpm. Should I spend the money to upgrade to an ECM while on single zone, or wait, or maybe don't do it at all? I like the idea of the pump helping decide gpm more accurately that Low, Med, or High.... My inclination is to wait until system is built out to 2 more zones on valves.....


  • hot_rod
    hot_rod Member Posts: 21,844
    Check the www.dsireusa.org to see if there are rebates on high efficiency upgrades in your area. Usually from the power providers, that might help make the decision 
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Big Ed_4
    Big Ed_4 Member Posts: 2,690
    No, the three speed Grunfos is fine....
    I have enough experience to know , that I dont know it all
  • GroundUp
    GroundUp Member Posts: 1,865
    It really comes down to your electric rates along with flow requirements of each zone. I was all about ECM for several years until I started having trouble with them. At this point, the payback in most residential systems (with my local power rate which is lower than most) is upward of 20 years and I don't foresee many of them lasting that long. I've gone back to the good old 15-58 variety of circs on the majority of systems, but I do use the Alpha 26-99 on occasion for higher demand systems.
    Alan (California Radiant) ForbesCurtTRich_49
  • Somewhat off topic:
    I use the Alpha I 15-58 when there are multiple zones, but recently needed to pump 10 GPM at 10' of head and the Alpha I was not strong enough. The Alpha II 26-99 is way too strong and there is nothing in between. Ended up using the larger pump anyway as Taco pumps aren't convenient from my regular suppliers. I left the differential pressure relief valve in place.
    Note to Grundfos: Give me a nice user interface screen on the Alpha II like you have on the Alpha I.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab