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Forensic Investigation:

ERF Member Posts: 51
After being in service for 23 years this pump froze up.  Can you guess what the problem might be? 

Was on a indirect HW tank running @ 2480 rpm's, drawing .81 amps,& 92 watts.  Boiler loop has a Grundfos Alpha running at constant pressure, supplying 4 home run loops of fin-tube baseboard with TR-V's. 


  • unclejohn
    unclejohn Member Posts: 1,757

  • Ironman
    Ironman Member Posts: 6,868
    I'll go with...

    It wore out.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • delta T
    delta T Member Posts: 870
    Yeah pretty much...

    23 years on wet rotor circulator (take your pick on brand, some are better than others) is not a bad life. Be satisfied that it lived a long fulfilling life and is now in a better place.
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,839
    I'll bite.

    Rust locked up the water lubricated bearings? Got their money's worth for sure. If there is THAT much ferric oxides in the system water, you can expect problems with the DCECM circulator a LOT sooner than that.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • ERF
    ERF Member Posts: 51
    forensic investigation

    Mark I believe you are correct. I ran a wire down the center of the impeller shaft and it was clogged with black iron oxide.  The shaft is bound up and is hard to turn by hand.  Not sure if that allows water to reach the rear bearing, as I am not ready to destroy the pump to find out.  Unit looks completely sealed except for the hole in the shaft. 
  • ERF
    ERF Member Posts: 51
    forensic investigation

    Mark I had installed the Alpha Grundfos about 3 years ago and system ran great on Auto until this year.  Noticed that baseboards was not heating properly with the weather we have been having.  Putting it into highest constant pressure mode helped , but still not satisfied , Return line in one  rather long loop is only warm to the touch. Next investigation will be the Alpha, as i understand this might be collecting a lot of iron oxide and restricting the flow. 
  • MikeyB
    MikeyB Member Posts: 696
    edited February 2014
    ECM and Iron

    ERF -Go to Eric Aune's article on his site mechanical-hub.com about ECM'S and systems w/iron, interesting read...............
  • Tim McElwain
    Tim McElwain Member Posts: 4,506
    Good old magnetism

    folks it does it all the time. Water treatment may help in some cases. I have 32 boilers I put in that I treated the water and only one has ever had a problem in over 18 years. I do not leave city water connected to any of my boiler installs. All are protected with LWCO's.
  • ERF
    ERF Member Posts: 51
    forensic investigation

    Yes, I read that article, that's what started me on my investigation.  I do not want to destroy the pump to get to the bearings.  Will try mild phosphoric acid like coca-cola to dissolve the iron oxide and free up the shaft.  Should be easy to wash out and not be to harsh. 
  • Derheatmeister
    Derheatmeister Member Posts: 1,280
    Try ..

    I have to deal with The "ferrous Invasion" on Wet rotor circulating Pumps Due to None Ox barrier install's on a regular basis..

    Fernox makes a Hypo cyclonic Magnetic Filter(TF1) ..The folks from Sentinel make something very similar..

    Using a Dry Rotor circ will also help...

    23 years is a long time for a Wet rotor Circ.

    I'd retire it and install a new one (It got its money worth)..Maybe a flush and Clean your system first...

    Looks like a 6 3/8" Flange to Flange ..They also come in Brass..
  • ERF
    ERF Member Posts: 51

    i would like to resurrect this circulator if possible because of the 4 speed function

    Will look into magnetic filter, thanks for the info, Ernie.