Well Pump Pipe Banging

I am not a plumber nor a well man (in more ways than one...), but I've managed to fix just about anything that has needed fixing in my life -EXCEPT this problem. I have banging pipes (one-two clunks) after my well pump shuts down. I have a typical old farm house well- replaced within the last 10 years. Submersible (3 1/2" I think- I know it was an unusual size stainless pump) down about 180 ft, 220vlt, about 20ft outside my house. There is a shut off valve at the bottom of my basement wall where it enters the home, then 3/4" copper across my basement (30 ft) to the pressure tank (19gal-brand new bladder tank). I have a typical little gray Square D pressure switch, and don't know what else to tell you. We get a banging after the pump shuts down. I'm getting the proper pressure readings 28/50+ -so I know the switch works and I replaced the bladder tank- but to no avail. The well installer said that the next time he had to work on the well, we might consider a new well since this one was getting shallow. It is just the two of us and we just don't use that much water- but could it be that we are running low. I'm unemployed (waiting for Mr. O to fix everything...- so before I call the well installer- I thought I would check with you smarties....Got anything that would help?

A well running low does not cause water hammer. You have a check valve sticking, or just to high of velocity through your pipes when the pump shuts off. If a new check valve on the pump doesn't help, I guarantee a Cycle Stop Valve will fix that problem. The CSV will reduce the flow from the pump to 1 GPM before the pump shuts off. This decreases the velocity through the pipes and makes sure your check valve is only open to 1 GPM, or the thickness of a piece of paper, before the pump shuts off. Makes it all nice and quite. BTW when you hear that clunk, your entire pipe system and fixtures have just experienced water hammer that can be 10 times the pressure you see on the gauge. So when the pump shuts off at 50 PSI, a 500 PSI shock valve travels through your system at 5,000 feet per second. That's what causes the "clunk". That noise is more than irritating, it can be devastating.

Well Pipes Banging

Thanks , "Valveman" ! I appreciate the fast response. Is the CSV valve something I could install on my lines in the basement (me?) or would that have to be done in the well itself (the well guy)? I can fix just about anything- but I can't raise 200 ft of pipe...I'm just about ready to call the well man- but I thought I would check with you first. Thanks again for your response!

P.s.

I looked up the site you suggested and it does look like something I could do - as long as it is above ground! Water Hammer is pretty frightening when you consider the power that is represented during the cycle! I would like to run and get one of these CSV valves today, if possible. What size would a residential system with a 3" submersible pump/ 3/4" copper pipes use? Is this something I can get locally (Minneapolis-western suburbs?) Once again, Thanks!
Fred

Anyone of three valves will work. The CSV150, CSV1W. or the CSV1Z. You can check with Goodin Company in Minneapolis at 612-588-7811. If they don't have one call me at 800-652-0207. Cary

Thanks again, Cary! Since they are a wholesaler, I'll have to go through my plumber- but will do so on Monday Morn! They have the CSV150. SoThat's what we'll go with. I'll let you know what happens once I put it on. Fred

Just a little update on my Well Pump Pipe Banging Problem...
I went ahead and purchased the Cycle Stop Valve and installed , but still am plagued with the banging of my pipes upon pump shutdown. Other than a nicer shower and the pump not coming on quite so much,( and some of that might be because we adjusted the pressure gauge a little...) we have seen little difference. I've double check to make sure we didn't get anything in the unit, drained the system, and I even dble checked the direction of the flow....
Soooo... at this point I give up. I called a well man and will meet with him the first of the week. He says he thinks it's a check valve as well. Says that it is probably part of the pump, so it might mean complete replacement. He DID say, however that we could possibly add the second check valve by the tank and it might work for now, although it wasn't the best of situations. (I haven't told him about the new Cycle Stop Valve yet....) OK- that's it for now. Thank you for being so responsive to this poor ole' man's ramblings! Have a great year!
Fred

If slowing the flow to 1 GPM before the pump shuts off didn't stop the water hammer, then your check valve must be really screwed up. It is probably sticking in the full open position until the flow reverses. Another check valve up top will probably solve that problem but, will probably make it start having water hammer on start up instead of shut down.