Bilge Pump Problem

Discussion in 'Boat Design' started by steve123, Feb 2, 2015.

  1. steve123
    Joined: Dec 2014
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    steve123 Junior Member

    Hi,
    Anyone come across this problem...Large Bilge pump self priming centrafugal runs fine until its actually pumping water then it vibrates like hell !!!!
     
  2. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    It could be a number of things. For example, it can be sucking air, the impeller may be loose, worn bearings.
     
  3. steve123
    Joined: Dec 2014
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    steve123 Junior Member

    There are 8 of these pumps on the boat, they are all brand new and 7 have this problem.
     
  4. gonzo
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    gonzo Senior Member

    What does the manufacturer say? I assume there is some kind of warranty.
     
  5. michael pierzga
    Joined: Dec 2008
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    michael pierzga Senior Member

    Sounds like air. Some vane segments are full of water , some vanes full of air .
     
  6. gwboats
    Joined: Sep 2005
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    gwboats Naval Architect

    Bilge Pumps

    If it is not a motor problem (rotor balance, electrical phase balance) then my guess is cavitation. Do the pumps have any sharp bends just before the inlet - these can cause flow problems. Best to fit a straight run into the pump of say length = to 8 to 10 pipe diameters.

    Cheers
     
  7. Poida
    Joined: Apr 2006
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    Poida Senior Member

    Post a pic of the set up.

    Poida
     
  8. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    What type of piping, how much "lift", pipe diameter?
     
  9. Kailani
    Joined: Apr 2013
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    Kailani Senior Member

    You didn't say what brand the bilge pumps are.
     

  10. kapnD
    Joined: Jan 2003
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    Location: hawaii, usa

    kapnD Senior Member

    Eight large bilge pumps?
    I'd say your problem is not with the pumps, but with the leaks in the hull!
    I have seen shaft corrosion issues on some submersible pumps that caused weakening and resulted in severe vibration, eventually breaking clear off.
    If they are controlled by a float switch, the "off" level may need to be adjusted so that it shuts off before it sucks air, which could cause vibration.
     
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