Iron pump on hot water loop?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by dwi, Jul 30, 2013.

  1. dwi

    dwi New Member

    Messages:
    3
    Location:
    south west MO.
    Hi,
    In my maintenance job I came across a small B&G circulating pump installed on a hot water loop in a 60+ room Motel. It isn't very old, less than a year. I found the box that it came in indicating it is an iron cast not brass. What problems should I be aware of to report to the owner? I'm sure the cost difference was
    the reason this happened.
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,319
    Location:
    New England
    Code requires it to be SS or bronze as I understand it. Because potable water has lots of dissolved oxygen, it will eat itself up fairly quickly, not counting the iron it adds to the water for potential stains on the sinks and showers. An iron pump is only okay in heating situations where it is a closed system - there, the oxygen gets purged fairly quickly and the water becomes somewhat inert.
    Last edited: Jul 31, 2013
  3. dwi

    dwi New Member

    Messages:
    3
    Location:
    south west MO.
    Are there any potential health problems connected with this sort of thing? Wouldn't the rust build up in the water heaters over time?
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,255
    Location:
    Cave Creek, Arizona
    There aren't any "health problems" unless someone starts drinking the hot water. The pump will rust and deteriorate fairly rapidly because of the oxygen in fresh water. Cost and lack of knowledge, are the two most common reasons. the "rust" will occur ON the pump and will stay there until the pump fails.
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,319
    Location:
    New England
    The rust particles could flow through the pipes and clog faucets and/or showerheads. Because it is being distributed to lots of places, the amount would be small at any one place, and it may not be noticeable. The 'proper' pump costs more, but maybe not when you consider that the iron one will need to be replaced sooner and could create some other issues along the way.
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,255
    Location:
    Cave Creek, Arizona
    If the particles detach from the pump, and they usually do not, they will go into the storage tank and fall to the bottom. The quantity would be very small so they would not "fill up" anything, nor would they gravitate to the faucets.
  7. dwi

    dwi New Member

    Messages:
    3
    Location:
    south west MO.
    Thank you both for your help. I may not get them to change it right now but they may just change it soon enough.

    dwi
  8. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,255
    Location:
    Cave Creek, Arizona
    Let it run until it freezes up or deteriorates to the point it no longer circulates.
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