Help with water hammers, please!

Discussion in 'Pumps and Tanks Well Forum & Blog. Water is life.' started by Eric70, May 25, 2018.

  1. Eric70

    Eric70 Member

    Joined:
    May 25, 2018
    Location:
    Colorado
    Hello all. I posted this in the main Plumbing Forum as well, yet thought this forum might be more relevant. I’m brand new to the forums, as well as being a first-time homeowner (who has a LOT to learn!). I moved into a home around a year ago that has a 810’ well. About 6-months ago, I started to notice loud “banging” in the utility room where the pressure tank and water treatment systems are.

    When the pressure tank gauge drops to 40psi, and the well pump is energized, the initial loud “bang” occurs. Then, when the pressure tank gauge rises to 60psi, and the well pump is de-energized, a series of loud “bangs” occur. I’ve had 6 plumbing professionals come over to take a look at this, and no one seems to have an answer as to what is causing this issue. One Plumber put on a new check valve and water hammer arrestor on the “well side” of the pressure tank. That didn’t seem to make much of a difference. The most recent Plumber thought that the new check valve installed wasn’t necessary, and perhaps was creating the water hammer/“bangs”. He took the check valve off and just put piping where it was, yet that didn’t alleviate the banging either.

    A couple have had theories that this banging may be caused from inside the well, and perhaps I need a new pump, check valves, and pipes. Although, my water pressure has not changed (it’s good) and the pump averages a flow rate of 10.3gpm (which I understand to be quite decent for well pumps in my area). I was just hoping you all may have some thoughts as to what may be creating these “bangs” (if indeed they are “water hammers?). Thank you very much for any insight you all may have!
     
  2. valveman

    valveman Cary Austin Staff Member

    Joined:
    Mar 15, 2006
    Occupation:
    Pump Controls Technician
    Location:
    Lubbock, Texas
    What horsepower is the pump and is it set at 800 feet?
     
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  4. Eric70

    Eric70 Member

    Joined:
    May 25, 2018
    Location:
    Colorado
    Hello. Unfortunately, all I have as documentation is the “Well Permit”, which lists the well depth at 810’ deep. I did have a well inspection and water test done when I went under contract on the home, yet it doesn’t show what the pump horsepower is, nor where the pump is set. According to the Well Permit, the well was constructed, and pump installed, when the home was built in 1995. The Seller of the home did not provide any documents regarding the well, so I have no idea if new parts were installed since it was built. If indeed no improvements/new parts were made since 1995, could the banging/water hammers possibly be an indication that the well needs a new pump, check valves, and piping?
     
  5. valveman

    valveman Cary Austin Staff Member

    Joined:
    Mar 15, 2006
    Occupation:
    Pump Controls Technician
    Location:
    Lubbock, Texas
    I think the hammer is caused by having more than one check valve in the well. Multiple check valves fight each other.

    There should be a control box for the pump that would tell you the horsepower.
     
  6. Eric70

    Eric70 Member

    Joined:
    May 25, 2018
    Location:
    Colorado
    I think that’s what the well specialist that came over a while back may have been thinking as well. If I’m looking at the right control box you’re referring to, it states: H.P. 2, R.P.M: 3450, AMP. 10.0

    I was a bit scared off when the well specialist said it would be “several thousand dollars” to replace the pump, check valve, and pipes (thus the reason I tried to get several other opinions). Yet if all that was installed back when the home was built in 1995, I’m guessing pumps and check valves probably start to show their age by this point? I would rather be proactive and spend the money now, versus having these violent water hammers do further damage.
     
  7. valveman

    valveman Cary Austin Staff Member

    Joined:
    Mar 15, 2006
    Occupation:
    Pump Controls Technician
    Location:
    Lubbock, Texas
    Ok now you know it is 2HP. So do a bucket test to see how many GPMs the pump will produce and we can probably guess the pump setting depth. Run enough hoses so the pump doesn't shut off and measure each with a bucket.
     
  8. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Where did that number come from? Open pipe at the well? Flow meter installed for testing at some point, and measuring the fill rate of the pressure tank?
    Here is another pair of numbers that can provide an estimate of flow:
    1. Here is another thing that can provide an estimate: If you stop using water as soon as the pump cuts on, how long does it take to go from the 40 psi cut-on to the 60 psi cut-off?
    2. What is the pressure tank model, or at least what is the nominal pressure tank size?
    The bucket test will be more accurate. When you do reach that steady state flow, also note the pressure of the water.

    While a CSV would probably not help the initial bang, it would reduce the shut-off bangs considerably. That would be because it would reduce the flow rate before the pump got shut off.
     
  9. Eric70

    Eric70 Member

    Joined:
    May 25, 2018
    Location:
    Colorado
    Thanks for your replies! I got that (average) flow rate of 10.3 GPM from a test done when I was under contract on the home, and had the well inspected. I just timed the pressure gauge, and it took 30 seconds to go from the 40 psi cut-on to the 60 psi cut-off. The pressure tank is a Champion, and Model # CM8003, Serial # 950514. There is a note on the bottom of a sticker on the tank that reads “Max. Work Pressure 100 psig” (I’m not sure what that means?). I couldn’t find what the pressure tank size is though?

    I’ve read about CSV’s, and thought that may be an option? Would you recommend installing one? Thanks once again!
     
    Last edited: May 27, 2018
  10. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    CH-32, 32 Gal Amtrol Champion Vertical Stand Well Tank.

    With a nominal 32 gallon tank, it is typically about 8 gallons from cut in to cut out. So with 30 seconds, that is about 16 gpm estimated. Incidentally, your tank is undersized for that pump. You normally want the pump to run a minimum of a minute.

    That could predict your water is roughly 200 or 3oo ft down at first guess. That does not indicate how far the pump is.

    Go ahead and do that multi bucket+timing test for better data.

    That indicates that you could pump the pressure up to 100 psi, after you set the precharge appropriately.

    The CSV could not fix your whole problem, but it would improve things for now, I think. It could also compensate for your smallish tank. Valveman is expert in that.
     
  11. Eric70

    Eric70 Member

    Joined:
    May 25, 2018
    Location:
    Colorado
    Thanks once again! I think I did the Bucket Test correctly (??). To empty the full pressure tank to cut-in of the pump, I got right at 5 gallons. And I re-timed the cut-in to cut-out, and it was 38 seconds. I believe this is the correct formula for determining GPM?

    38 seconds / 60 = 0.63

    5 gallons / 0.63 = 7.93

    So that would mean my pump is delivering roughly 8 gallons per minute?
     
  12. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    So 5 gallons was your drawdown. Your calculation is correct.

    Valveman, I think was envisioning you running two or more faucets with the pump on. He was saying that you would get enough water being consumed, maybe from 3 spigots, that the pump pretty much settled at a pressure, such as 50 PSI. You would time the filling of your Homer bucket, and do the calculation of flow rate from each spigot.

    Your test has validity, and is simpler. However I wonder why it differs a fair amount from the 10.3 number. Anyway, your 7.93 gpm number could be from a 7 gpm pump about 380 ft down to water, or a 10 gpm pump at about 480 down to water. These are rough calls, but maybe close enough for now.

    So where you are now is whether you get stuff changed out now, or think about working around the problem trying to postpone the several thousand dollar expenditure. I don't know the right move. The CSV reducing the cut-off bangs has its advantage. Then, if you get a failure later, be ready to get the pump guy out as quickly as possible.

    I am curious if your pump is on galvanized or maybe schedule 12o pipe. Your new pump guy -- is he in favor of multiple check valves, or just one? Galvanized or PVC. There are different reasonable opinions. I am not a pro, but for drinking, I think heavy PVC is usually better, stainless couplers, and the check valve in the pump and one right above the pump is best usually. If you did not have the multiple check valves, then you would not have gotten your banging.
     
  13. Eric70

    Eric70 Member

    Joined:
    May 25, 2018
    Location:
    Colorado
    I was wondering the same as to the 10.3 that was determined during the well inspection, versus what I just got? The inspection was done a year ago, so I’m kind of curious as to the different results between then and now.

    If doing what the well pump guy said he would suggest (replace basically everything in the well) will fix this problem, then I’m all for it. He assumed that the pipes in there now are copper, so he would replace them with a PVC type of pipe. We didn’t talk at the time about specifics on check valves and so forth, but I’m hoping to get a call back from him to discuss his plan, and get an estimate on the cost.

    The only information I have on the well is from the Well Permit, and that states that the well was drilled, and pump installed, when the home was built back in ‘95. If no replacements have been made since then, which I assume may be the case, I may be “on borrowed time” on the life expectancy on the pump, and other parts in there? If that’s the case, then it may be time for a full overhaul of the well anyhow?? Are well pumps and check valves in there designed to last 20+ years?

    Thanks once again for all of your time, thoughts, and expertise! I’m learning a LOT, and have MUCH more to learn!
     
  14. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    I expect he suspects the pipe going down to the well now is galvanized. Maybe he said metal, and you pictured copper.

    So he likes the PVC pipe. Good.

    There is a lot to be said for getting it done right, rather than working around the problem for a long time.
     
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