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Grundfos Alpha and zone valves and pump curves

timo888 Member Posts: 137
There is a statement on the Taco HVAC site recommending pumps with relatively flat curve if the system has zone valves:

< In systems using zone valves (or manifold valve actuators) select a circulator with a relatively flat pump curve.This minimizes changes in differential pressure as the zone valves open and close. (See TD01, When Zone Valves Close, for additional information.>

<a href="http://www.taco-hvac.com/uploads/FileLibrary/SelectingCirculators.pdf">http://www.taco-hvac.com/uploads/FileLibrary/SelectingCirculators.pdf</a>

What is the Grundfos Alpha's pump curve? Is it possible to drop a Grundfos Alpha into a system with Taco zone valves?

Will the Alpha "learning" mode in any way get bollixed up by the zone valves' opening and closing? Or is the Alpha actually well suited to this scenario?

Will using a single Alpha to supply two zones of different type (indirect water tank and radiators) present a problem? How does the Alpha recognize which of three possible scenarios is in effect-- DHW zone, radiator zone, both?


  • NRT_Rob
    NRT_Rob Member Posts: 1,013
    depends on the mode

    if you're in a constant pressure mode, the curve is absolutely flat... you get 6, 9, or 12 feet of head constant as long as you don't exceed the max flow rating.

    I don't use autoadapt.

    you could get into trouble if you can't balance flow when all zones are open. but as long as there is balancing and you aren't exceeding the ratings and you have priority or the same water temp requirements for all your loads, you can make one pump do many things.
    Rob Brown
    Designer for Rockport Mechanical
    in beautiful Rockport Maine.
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