Loop Circulator Selection

Discussion in 'Geothermal Loops' started by mtrentw, May 29, 2012.

  1. mtrentw

    mtrentw Active Member Industry Professional Forum Leader

    Will be sharing a 5 ton loop between a 3 ton and 2 ton Comfort-Aire. Some basic head loss calcs are showing, with units running at 9 GPM and 6 GMP respectively, a total head loss of 40' and 32' respectively.

    Anyone with similar setup have good or bad options/experience for a set of pumps.

    Looked at so much pump curve data, it is hard to get a good pick and optimize performance.

    How much of a difference in power would the high end pumps make.

    Too many options with Grundfos, Taco, Wilo, B&G.

    Anyone with installed power data on the Grundfos Magna.

    Often times it is better to hear "I have this and in similar situation and it worked great" rather than try to fit a system to a curve.

    Last edited: May 29, 2012
  2. zacmobile

    zacmobile Guest

    loop circulators

    Usually what's done because of the relatively high head of geo ground loop pumping applications is to put two circulators in series, ie. two grundfos 26-99's front to back, thereby doubling your pumping head. What's even more usually done is to install a pre-built pump station from the heat pump manufacturer or direct from a whole host of pump station manufacturers.
    Geo-Flo Products Corporation - Double O-ring OEM Modules
    B & D Mfg., Inc. | Geothermal Flow Centers | QT® Flow Center
    etc. etc.

    Attached Files:

  3. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Need more info. Is your loop already in the ground? The pressure drop at 40 ft of head and 32 ft of head is that at 9 gpm and 6 gpm? How much is the pressure drop through the loopfield when the it is running at 15 gpm when both heat pumps are on? The last thing you want is two circulators turn on when only one of the heatpumps goes in 1st stage. Would be a total waste. We see runtimes around 3700 hours per year and heatpump, probably more in your case. You do the math how it will cost you.

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