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New Member


Wednesday, March 22nd 2006, 12:45pm

Hunter PGV Water Hammer?

I have installed Hunter PGV Jar-Top valves with Flow Control and noticed while flushing the lines by manually turning the solenoid on and off, the valve chatters for a second or two when closing. I do not have the controller wired yet. I did not install an air column on the main line. Is this chatter normal? Is it damaging to the valve? Should I retrofit an air column in the line?? I'm on a well with 25 - 55 PSI.
Thanks in advance for any inputs...


Supreme Member


Wednesday, March 22nd 2006, 4:55pm

I don't think it is the type of valves...I bet most other valves would do it also.

My guess..and it is really an educated guess as I am not there!

Low volume can cause the valve to do is a fairly slow closing valve anyway....and even more so if the volume going through the valve is "rushing" to try and fill the pipes and operate the sprinklers.....when the solenoid pin closes down over the port there is a bit of a delay as the water fills the top of the diapragm.....causing it to try to close, causing the diapragm to "pop" up and down and eventually close.

How is that for a simplified, layman term type of explanation....?

Try this:

With the valve running the zone....turn the flow control down until it starts to affect the flow will see the sprinklers radius start to decrease and you will hear the valve restrict the flow and feel it in your hand on the flow control....then open the flow control until that "feeling" goes away and the heads come back up to full radius....then shut it down and see if it helps.

Let us know please.
Sprinkler Solutions, Inc.
Arizona and Colorado


New Member


Thursday, March 23rd 2006, 1:40am

Thanks SprinklerGuy... Your explanation makes sense. I think the best bet at this point is to go ahead and finish the install. After the heads are all in, the dynamics will change significantly from open ended pipes. At that point if it is still a problem I can tune the flow rates, or even add an air chamber.
Thanks again,


Supreme Member


Thursday, March 23rd 2006, 3:20am

You didn't mention the pipes were open! LOL!

Then I am surely correct in saying it should be fine...unless of course the total amount of GPM in the heads you will eventually install on each zone is equal to...blah blah blah... ;)

Let us know.
Sprinkler Solutions, Inc.
Arizona and Colorado


Supreme Member

Posts: 5,376

Location: Metro NYC


Thursday, March 23rd 2006, 3:26am

You can get improved valve operation and service life if you do adjust the flow controls on the valves, as was described earlier. You would do this after all the heads and nozzles are in place. Even with everything in good operating order, the first time a sprinkler system is turned on in the spring (in freezing climates where the pipes were blown out with an air compressor the previous fall) the valves may bang a bit until the air rushes out of the heads.

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