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Pump Curve Help Please

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Bostopa
Bostopa Member Posts: 12
in THE MAIN WALL

Hi all I'm looking at two Grundfos pumps both 15-58FRC & 15-58UPS.

Trying to figure out do both have the same curves or are the different. I dont understand the curves from the two.

15-58FRC.jpg

15-58UPS below

15-58UPS.jpg

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 27,125

    Yes and no. The top graph shows the actual inherent performance curves for the pump operating at three different power levels. That graph shows what the pump — without other controls — will accomplish. The bottom diagram shows the effect of three different electronic control strategies which the "e" version oof the pump can be programmed to do:

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • hot_rod
    hot_rod Member Posts: 27,171

    The first set of curves shows the 15-58 with and without the internal check valve, so a small difference.

    The "c" in the model number is for internal check valve versions. FR is for flange rotated versions.

    Screenshot 2026-02-11 at 10.06.02 AM.png
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Bostopa
    Bostopa Member Posts: 12

    Can the second curve/pump depending on how its programmed/set mirror the first pumps curve or are the completely different….just trying to undertstand is it worth buying the 15-58 UPS

  • Jamie Hall
    Jamie Hall Member Posts: 27,125
    https://forum.heatinghelp.com/discussion/comment/1887433#Comment_1887433

    The pump itself is exactly the same. The difference is in the controls.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Bostopa
    Bostopa Member Posts: 12

    Its for monoflo system not sure if going from FRC to UPS gets me anything

  • GGross
    GGross Member Posts: 1,819

    The pump is identical it is just showing with and without the internal check valve.

    the base model is UPS15-58 then you may find FR FRC FC the "R" is for rotated flange, the "C" means it comes with a check valve. Either way the base model will start with UPS15-58

    Be aware when you buy one the boxes now have all of those model number variants on them, the specific variant can always be identified with the long form part number if needed for example the US version of the UPS15-58FC has a long form part number 59896341 the rotated flange variant ends in 3 instead of 1

  • hot_rod
    hot_rod Member Posts: 27,171

    MonoFlo systems can have a high pressure drop, what circulator is currently on it?

    Ideally you want to run in the middle 1/3 of the curve. So that 15-58 is comfortable in the 5-11 gpm range. Head depends on which speed. So about 8 gpm at 12' on speed 3.

    Is the system zoned? TRVs on radiators as an example? If so an ECM delta P circ, the Alpha or Magna series, is a good match up.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream

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