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Hot Water Recir ?

GRCourter | Posted in General Discussion on December 5, 2008 06:15am

Ok it has me stumped.  Customer had a recirculation line put in 8 years ago.  3/8″ line comes off the HW line at the kitchen sink (furtherst point in the system) and goes thru a Grundfos and goes into the hot water tank at the drain outlet.  The pump is wired to the circuit panel.  It had been working for 7 years and then the pump went bad, I replaced the pump with the same model and the system worked fine for a year.  Now the pump will not shut off.  What am I missing?  How is this supposed to work.  For the first 7 years the pump would come on and off at various times, now it will not shut off.  Any and all ideas are appreciated.

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  1. DanH | Dec 05, 2008 06:44am | #1

    There is a thermostat somewhere, probably under the sink or next to the pump, that controls the pump. The stat has gone bad or someone's mucked with it.

    The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
    1. GRCourter | Dec 05, 2008 04:47pm | #2

      Thanks, but there is not a thermostat.  I have replaced the A/C ducts, insulated the floor joists, put in radiant heating, I have been all over the plumbing lines and there is not a thermostat or sensor anywhere.  The plumber that installed it has since retired and the HO has been unable to reach him.

      1. DanH | Dec 05, 2008 05:46pm | #3

        Well, if it turned itself off there was either a thermostat or a timer. Trace where the power for the pump comes from. Could be imbedded in the pump, I suppose -- check the papers that came with the new one, if you can dig them up.
        The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel

  2. User avater
    SteveInCleveland | Dec 05, 2008 06:44pm | #4

    I've used one by Laing on numerous projects.  One model I use has no timer on it, the othe does have a timer on it.  Clients can always plug the one the has no timer into a timer plugged into an outlet.  Otherwise, without a timer, the ones I use run 24-7.

    http://www.lainginc.com/

    just click on the "recirc pumps" link on their home page to see the kind I use.

       

     

     

     

    "Preach the Gospel at all times; if necessary, use words."  - St. Francis of Assisi

  3. User avater
    Dam_inspector | Dec 05, 2008 06:48pm | #5

    tHERMOSTAT IS INSIDE THE PUMP.

    Just guessing but.... something made it work for a year.

    1. DanH | Dec 05, 2008 07:00pm | #6

      Of course, it could be that the thing was plugged into an appliance timer, and someone removed the timer to use it as a vacation timer.
      The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel

      1. User avater
        Dam_inspector | Dec 05, 2008 07:09pm | #7

        The grundfos website shows there is a temp sensor at the pump. I don't know if it's internal though. The crude graphic shows it like it may be outside the pump, but the graphic is so basic that it could not be shown inside it.

        1. DanH | Dec 05, 2008 07:11pm | #8

          Does the web site give the specs? If so they should spec the thermostat somehow, if it's imbedded.
          The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel

          1. User avater
            Dam_inspector | Dec 05, 2008 07:45pm | #9

            I don't know which pump he has, and I didn't check the specs on any of them. I'm pretty sure the info is in there someplace.

          2. GRCourter | Dec 05, 2008 08:50pm | #10

            heading to the Grundfos website now

          3. BoJangles | Dec 05, 2008 08:57pm | #11

            Don't know which pump you have, but the thermostat setting on many of them is very small and you may have not seen it.

            The pump shouldn't look like your typical hydronic heat pump.  It should be much smaller and either run off a timer or a thermostat at the pump.  Both of which are sometimes hard to see unless you know what to look for.

          4. GRCourter | Dec 05, 2008 09:15pm | #12

            Ok, I do not have the old pump, but when I took the model # off the old name plate and had my supplier order it, it looked the same and I checked the #'s and they were correct.  I don't know how the system worked and there is not any adjustment in the pump (ie, temp control) and there is not any thermostat contol outside the pump, and the power line runs 24' to the breaker panel.  Now there is a fitting between the isolation valve and the input into the tank which I have assumed was a check valve, naybe this is a bad assumption.

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