Water Hammer Issue?

Discussion in 'Pumps and Wells' started by ShawnInPaso, Mar 18, 2018.

  1. Mar 18, 2018 #1

    ShawnInPaso

    ShawnInPaso

    ShawnInPaso

    Member

    Joined:
    Jan 7, 2014
    Messages:
    11
    Likes Received:
    0
    Location:
    ,
    Hello,

    I've searched this sub-forum but couldn't find the solution to my issue.

    My well system consist of a below ground pump which fills an above ground tank. There is a booster pump on the outlet of the above ground tank and a pressure tank, etc. When the pressure tank gets to less than 40PSI, the booster pump kicks on and then shuts off at 60PSI. When the booster pump shuts off, there is an obvious "water hammer" in the house. A couple of times the pressure was enough to blow water out of a flex pipe under a bathroom sink.

    So I am at a loss why the water hammer occurs and how to correct it? I have researched the issue but have just become more confused. :confused:

    Attached is a photo of the system.
    Any guidance would be very much appreciated.

    Shawn

    sys config.jpg
     
  2. Mar 18, 2018 #2

    Geofd

    Geofd

    Geofd

    Professional Professional

    Joined:
    Jan 20, 2018
    Messages:
    294
    Likes Received:
    42
    Location:
    Boston, Massachusetts
    i would try a spring loaded check valve on the main in the house before any fixtures.... see what that does
     
    ShawnInPaso likes this.
  3. Mar 19, 2018 #3

    Valveman

    Valveman

    Valveman

    Pump Controls Tech Professional

    Joined:
    Jan 6, 2010
    Messages:
    390
    Likes Received:
    82
    Location:
    ,
    The bladder in the tank is most likely bad. The pump should run for a minute or so to fill that size tank, not a few seconds. Also the pressure switch on the motor is too far from the tank.

    You also already have a spring loaded check valve. it is the brass item on the inlet to the pump, not the union you have circled in red.

    The bladder/diaphragm in the tank is broken from cycling the pump on/off too much. The diaphragm goes up and down with each pump cycle and breaks like bending a wire back and forth.

    When replacing the tank it is a good time to install a Cycle Stop Valve. It will give you constant pressure to the house instead of constantly varying pressure. Plus it will work with a much smaller pressure tank and doesn't let the tank bladder, check valve, pressure switch, pump and everything else be cycled to death.

    Jet Pump PK1A.jpeg
     
    ShawnInPaso likes this.
  4. Mar 19, 2018 #4

    ShawnInPaso

    ShawnInPaso

    ShawnInPaso

    Member

    Joined:
    Jan 7, 2014
    Messages:
    11
    Likes Received:
    0
    Location:
    ,
    Thanks for the help guys.

    The pressure tank does hold pressure okay and takes ~30 seconds or so to fill so I'm not sure it is bad or why it would be the culprit with the water hammer issue (then again I am just now having my first cup of coffee :) )?

    The Cycle Stop Valve looks interesting, I will certainly check it out.

    EDIT to add: You're right, I circled the wrong item !
     
    Last edited: Mar 19, 2018
  5. Mar 20, 2018 #5

    ExtraMilePlumbing

    ExtraMilePlumbing

    ExtraMilePlumbing

    Well-Known Member

    Joined:
    Aug 21, 2014
    Messages:
    438
    Likes Received:
    67
    Location:
    ,
    Where do you hear the noise, do you have water hammer arresters in the house? Maybe a strap came loose, try to pin point where the noise is coming from? It could be a bad cartridge
     
  6. Mar 20, 2018 #6

    ShawnInPaso

    ShawnInPaso

    ShawnInPaso

    Member

    Joined:
    Jan 7, 2014
    Messages:
    11
    Likes Received:
    0
    Location:
    ,
    Thanks EMP. It's generally coning from one corner of the house. Good idea to pinpoint the location but I must say it seems like it's sort of rattling a length of pipe. Not sure what you mean by a bad cartridge?
     
  7. Mar 20, 2018 #7

    Valveman

    Valveman

    Valveman

    Pump Controls Tech Professional

    Joined:
    Jan 6, 2010
    Messages:
    390
    Likes Received:
    82
    Location:
    ,
    If that is a 40 gallon size tank then filling in 30 seconds would be about right. If that is an 80 gallon tank it should take a minute to fill, which means the tank is only holding 50% as much as it should. When there is water on top of the diaphragm, the tank cannot cushion the water hammer.

    And yes you can strap things down to try and keep the water hammer from making so much noise and/or breaking the pipes. Or you can fix the original problem and make the water hammer go away. Replacing the tank may give some cushion to catch the water hammer. Adding a CSV to give a mechanical soft start/soft stop will eliminate the water hammer altogether, and has several other benefits.
     
  8. Mar 20, 2018 #8

    ExtraMilePlumbing

    ExtraMilePlumbing

    ExtraMilePlumbing

    Well-Known Member

    Joined:
    Aug 21, 2014
    Messages:
    438
    Likes Received:
    67
    Location:
    ,
    Every plumbing fixture has a cartridge or stem to control the water supply, (single handle faucets are known for corroding and creating water hammer)pin point by turning on one fixture at a time and have someone else listen, also inspect the water pressure , it shouldnÂ’t be more then 80 psi.
     
  9. Mar 20, 2018 #9

    Valveman

    Valveman

    Valveman

    Pump Controls Tech Professional

    Joined:
    Jan 6, 2010
    Messages:
    390
    Likes Received:
    82
    Location:
    ,
    Yes it is true that any/every faucet or valve in the house can cause water hammer. But in this case the water hammer is happening on pump stop. This water hammer happens because the pump is producing maximum flow when it gets to 60 PSI and shuts off. At max flow the check valve in the pump is wide open when the pump shuts off, which causes water hammer when the check valve slams shut.

    A CSV will reduce the flow to 1 GPM when filling the tank to 60 PSI. So when the pump shuts off the check valve is only open to 1 GPM, which is only the width of a piece of paper. The check valve closes from only the 1 GPM position, not wide open, so there is no water hammer.

    Anytime you hear or feel a water hammer "thump", the pressure in the system has just spiked at 5-10 times more pressure than the pump can even build. That is why it will break a 200+ PSI rated pipe when the pump is only working from 40 to 60 PSI.

    Water hammer can also be caused when the toilet float valve or washing machine solenoid valve closes to quickly. To prevent this I adjust the ball cock to the toilet and the fill valve to the washing machine to slow the fill rate. The toilet and washing machine do not fill as fast, but this eliminates water hammer from happening when these valves close.
     
    Last edited: Mar 21, 2018
  10. Mar 21, 2018 #10

    ExtraMilePlumbing

    ExtraMilePlumbing

    ExtraMilePlumbing

    Well-Known Member

    Joined:
    Aug 21, 2014
    Messages:
    438
    Likes Received:
    67
    Location:
    ,
    Awesome post valveman , very knowledgeable
     
  11. Mar 22, 2018 #11

    ShawnInPaso

    ShawnInPaso

    ShawnInPaso

    Member

    Joined:
    Jan 7, 2014
    Messages:
    11
    Likes Received:
    0
    Location:
    ,
    Thank you for the extra knowledge and info EMP and Valveman. The water hammer definitely occurs when the booster pump stops pumping.

    Sorry to say I don't know the size of my pressure tank so I'll have a look at it later today.

    Anytime you hear or feel a water hammer "thump", the pressure in the system has just spiked at 5-10 times more pressure than the pump can even build. That is why it will break a 200+ PSI rated pipe when the pump is only working from 40 to 60 PSI.

    This is my main concern .....looks like a CSV is in order.
     
  12. Mar 23, 2018 #12

    Valveman

    Valveman

    Valveman

    Pump Controls Tech Professional

    Joined:
    Jan 6, 2010
    Messages:
    390
    Likes Received:
    82
    Location:
    ,
    A CSV by itself may solve the problem. But you may still have to replace the check valve if it is too far gone.
     
    ShawnInPaso likes this.

Share This Page