Results 1 to 7 of 7

Thread: Water Hammer and a well

  1. #1
    Guest

    Water Hammer and a well

    I had an addition to my house put on about a year and a half ago and now have incredible water hammer problems. I do not know if the two are related?
    I have been living in my house since 1988. When the banging started about 3 months ago I tried to ignore it until it sounded like a sledgehammer! I called the well expert out and he indicated there was a leak on the internal 1 ½” pipe (as opposed to the casing which is O.K.). He said the internal pipe in our area lasts about 30 years then we can expect problems. I gave him $500 and let him do his thing. He may have solved one problem but the other is still there.
    I could not find the Check valve and pray my plumber did not put it under the driveway!
    Does anyone have any ideas on how I should diagnose this situation?
    Thank you!


  2. #2
    Member
    Join Date
    Sep 2002
    Location
    Rocky NH Coast
    Posts
    76

    Re: Water Hammer and a well

    Buster,

    Turn the pump off at pressure then cycle the hot/cold water lines on/off several times at various locations. If it's noisy then its in the supply lines, if not then it's the pump.

    Seems like 1.5" is a pretty big line from a well, and what did the well expert do? Put a check valve in? Presumably you paid him to diagnose and fix the problem so one would assume he might offer a solution not only if it's the pump but the house system as well. If there was a suply side leak that could introduce air to the system which you should notice..

    It is typical to get some water hammer when the pump turns on and off more so when the well is deeper since there is more water in the pipe/system to cause this.

    We get some water hammer from the hot water side of our system but it's like someone tapping once on the floor - nothing loud.

    There are devices (standpipes) plumbers can put in the household system to minimize this effect, so I would suggest consulting them after having a discussion with the water expert that did the previous work.

    Carl






  3. #3
    Senior Member
    Join Date
    Sep 2002
    Location
    Nova Scotia,Canada
    Posts
    3,108

    Re: Water Hammer and a well

    Water hammer:
    Probably doesn't have a thing to do with the well or pump as that all feeds into a pressure tank that supposedly has an air blanket or air bladder which has a dampening effect on the pressure waves. If only an air blanket the tank may be what is called waterlogged and you may have to pump air into it.

    Do as Carl suggested and check the plumming downstream from the tank for standpipes, Exspecially ones at the higher points.
    Also with the system in normal operation on a valve by valve basis fully open and quickly close all the valves in the system. It may help pinpoint the location which is causing the hammer.
    If it is really bad a small 2 gallon watertank with an air bladder tied into the far end of the system may help. Also check the pressure at which your system is operating. I beleive 60 psi is normal.

    Disclaimer: my knowledge of plumbing ends at knowing water runs downhill.

    Egon

  4. #4
    Member
    Join Date
    Sep 2002
    Location
    Fort Kent, Maine
    Posts
    59

    Re: Water Hammer and a well

    Hydraulic transient Valve Closing Pressure surges are produced by unsteady flow resulting from either acceleration or deceleration of a liquid. Every flowing fluid accumulates kinetic energy (velocity head), the strength of which is determined by the weight of the fluid and the speed with which it is moving. If the speed of this fluid is changed, i.e., suddenly slowed or stopped, the kinetic energy is transformed into pressure energy and causes the normal system pressure to increase. This phenomenon is called hydraulic transient or, more often, "water hammer". If left uncontrolled, it can produce forces large enough to damage a piping system permanently.

    Several common causes of hydraulic transient are:

    1) Sudden opening or closing of valves in a pipeline

    2) Starting or stopping the pumps in a pumping system

    3) Operating errors or malfunctioning of equipment.

    Without knowing more about your system, I'm going to suggest that your pressure tank is faulty. As someone suggested, either the bladder is ruptured, or you need to add air. Make sure your pipe hangers aren't too tight to the pipe, they need to slide a bit. Make sure that the pipes don't come into contact with a wall. stud, joist or other obstacle after making a 90 degree bend.Experiment to see which valve causes the hammering, might give you an idea on which line is bad. (Just remember, the hammer can be on another line)
    <font color="red">So others may live</font>

  5. #5

    Re: Water Hammer and a well

    Let us know a little more to help diagnose the problem. Does the water hammer occur when opening and closing valves (faucets), or when the well pump starts and stops? Your pressure tank serves 2 purposes, first, it provides a reservoir of pressurized water, so that your "low volume" water needs are met from it, rather than constantly cycling the well pump. In addition, it provides a cusion to the impact of water in the lines. Think about it-depending on your well system, you may have several hundred feet of line, with water in it at 8.3 lbs per gallon, meaning perhaps 100 plus (maybe way plus) pounds of water that you are trying to instantly stop with your valve.

    A couple of things to consider. Check at your pressure tank, or well controller. Have someone open a faucet, and get an idea how long it takes your pump to start. If it is nearly instantanious, your pressure tank probably needs charged, or the bladder is shot (assuming a bladder type tank), and needs replaced. You want to do so pretty quickly, overcycling the pump is hard on them.

    If the pump seems to cycle normally (make a guess at the size of your tank, 40-80 gallons is pretty common) and if it takes a few minutes to bleed down and the pump to come on, the pressure tank is probably fine. You can also shut the pump off (turn off the breaker), drain your tank (open a valve till no water comes out) and check the pressure in the tank with a tire gauge. It should be a bit under the low-pressure setting on your pressure switch.

    How far is it from your pressure tank to the house, or is it in the house? If there is a long run from a seperate pump house, you still have alot of mass of water in the lines-a pressure tank in the houses may be a good idea. You can also add water-hammer arrestors at each faucet-they are a small air chamber, often made up on site from a capped length of pipe. The cap is installed vertically, at a tee before the faucet, and traps a small amount of air.

    Let us know a little more and maybe we can help.

    Bri

  6. #6
    Member
    Join Date
    Sep 2002
    Location
    Fort Kent, Maine
    Posts
    59

    Re: Water Hammer and a well

    <font color="blue"> It should be a bit under the low-pressure setting on your pressure switch. </font color>

    It should be 2 pounds under the pressure setting.
    <font color="red">So others may live</font>

  7. #7
    Senior Member
    Join Date
    Sep 2002
    Location
    Nova Scotia,Canada
    Posts
    3,108

    Re: Water Hammer and a well

    You can also check the pump cycle time by watching the tank pressure guage. It should reach a low, pump start, setting and then increase to a high, pump shutoff setting. The difference between the settings should be about 15 # give or take. Depending on type of pump and relay positions you may even be able to hear the relay open or close.
    I have a feeling your water tank is waterlogged. That said look in some other spot to find the real problem!!!!

    Egon

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •