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Grundfos Pump Housing Temperatuire

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J Van Lund
J Van Lund Member Posts: 19
in Radiant Heating
The outside housing temperature on a 12-year old Grundfos UP15-42has a temperature increase of 10 to15F over the circulating water temperature inside the circuits. Water temp 110F; outside pump temp 125F. Is this a cause for concern or replacement?

Comments

  • Mark Eatherton
    Mark Eatherton Member Posts: 5,875
    I believe they rate their motors for a given temperature above ambient, not the circulating water temperature. Its usually listed on the motor.

    Only way to know for sure if you are in trouble is to check the motor amperage. And even that isn't much help, because some of these little motors draw the same amperage with a locked rotor as they do under normal full load.

    ME
  • Steve Minnich
    Steve Minnich Member Posts: 2,868
    What Mark said - check the amp draw. The pump is rated for water temps in excess of 200*F.
    Steve Minnich
  • hot_rod
    hot_rod Member Posts: 26,449
    Are you sure it is circulating, not air locked. if the temperature continues to increase it may be air locked

    The motor will add some heat it is a 42W motor, some is pumping energy, some heat.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    GGross
  • SWEI
    SWEI Member Posts: 7,348
    The efficiency of small PSC motors is abysmal. The other 75% of that energy has to go someplace.
    Gordy
  • goodend
    goodend Member Posts: 6

    Grundfos ups15-58fc with hot water heater for floor heat at 80F but pump warms up to 135-155F. I suspect air in system and will install t pipe at highest point in system to bleed air. Does this pump have bleed screw,?

    6724.jpg
  • hot_rod
    hot_rod Member Posts: 26,449

    if you pop that black label off, some models have a large screw below that you can purge some air.

    Or loosed the top flange bolts and burp it. Be careful if it has been dead headed there could be a steam discharge

    The checks can sometimes fail inside that volute and cause a blockage or restriction.

    The motor will run a bit warmer than the fluid it pumps

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    goodendGGross
  • goodend
    goodend Member Posts: 6

    Hot rod..Ru from rogersville?

  • hot_rod
    hot_rod Member Posts: 26,449
    https://forum.heatinghelp.com/discussion/comment/1875037#Comment_1875037

    formerly, been in Utah about 4 years now.

    Is this a system down near Branson by chance?

    That looks like a fairly new pump, I think the PC indicates the 3 week of 2024 manufacturer date.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • goodend
    goodend Member Posts: 6

    1989 you installed a heat system in my 2 story house add on just s of hywy 60 off u hywy. Gypcrete floor one and heat transfer panels under second floor. I think you were building a subaru side by side for your son. I just built in eureka springs ark and troubleshooting new system. You were correct once you have a heated floor you'll never go without. Thanks for all your influence and help.

    hot_rodGGrossHeatingHelp.com

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