Water Hammer At Pump Cycle Stop

Discussion in 'Pumps and Tanks Well Forum & Blog' started by terrysii, Oct 3, 2008.

  1. terrysii

    terrysii New Member

    Messages:
    9
    My son-in-law's submersible pump has developed a loud hammer at the end of the pump cycle. The system also appears to be losing some pressure slowly (We've checked for leaks in the above-ground system). Suggestions?
  2. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    Do you have any additional check valves beside the one in the pump?

    bob...
  3. terrysii

    terrysii New Member

    Messages:
    9
    None that I am aware of. Certainly none close to the pressure tank where I was observing it. Would it help to have one close to the pressure tank? The pump has worked without problems for the four or five years they have been in the place, but recently he pumped a substantial amount of water at one time while filling a hot tub. The system coincidently lost some of the charge in the pressure tank - its a non-bladder type older tank. If that gives you any clue.
  4. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    Using a lot of water wouldn't cause water hammer. The tank may or may not be waterlogged but that wouldn't cause water hammer either. You have a check valve somewhere going bad. Either in the pump or somewhere in the line from the tank to the pump.

    bob...
  5. terrysii

    terrysii New Member

    Messages:
    9
    Thanks for your advice
  6. eldyfig

    eldyfig New Member

    Messages:
    32
    Location:
    Folkston, GA
    New member here. Found the forum while searching for well info. I post on a couple woodworking sites; Woodnet. Also frequent MyTractorForum. Looks to be some good info here. I have read some in this Pumps and Wells Forum. Have a couple questions though.

    My well pump that pumps to the aerator tank hammers when it shuts off. Also noticed that it loses a slight bit of pressure when the pump cuts off even though the aerator tank is full and the float valve is closed.

    I have noticed very slight leaks where the piping connects to the casing on the suction side and on the discharge side. I can hear air escaping from where the well pipe enters the well casing also. It lasts for about 2 seconds. There isn't any check valve installed.

    Could these leaks be causing the hammer when the pump shuts off? My house pump/tank that is supplied from the aerator tank, has no leaks and shuts off calmly.
  7. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    The leaks wouldn't cause water hammer, but a worn out check valve spring could. This could be the valve in the pump. It would make a difference too if the pump in the well were pumping into a pressure tank first or just pumping straight into the aerator and being controlled by a float switch.

    bob...
  8. eldyfig

    eldyfig New Member

    Messages:
    32
    Location:
    Folkston, GA
    I apologize. I didn't explain it fully. My well pump is sitting on top of a bladder type pressure tank that supplies pressure to the aerator. Looking at the part list for the pump, I could not find a check valve in the pump.
  9. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    The check valve is probably in or near the well then. Is there one pipe or two pipes going from that pump to the well?

    bob...
  10. eldyfig

    eldyfig New Member

    Messages:
    32
    Location:
    Folkston, GA
    One pipe. Pump is a StaRite SND-L.
  11. Gary Slusser

    Gary Slusser That's all folks!

    Then you have a foot valve on the end of the drop pipe in th well.
  12. eldyfig

    eldyfig New Member

    Messages:
    32
    Location:
    Folkston, GA
    Is it normal to hear air escaping from where the well pipe enters the well casing after the pump kicks off?
  13. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    Yes, that is the air that was drawn into the well casing when the pump kicked on and lowered the water level. The pump kicks off, the water comes back up to it's static level and the air is pushed back out.

    bob...
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