You are not logged in.

Dear visitor, welcome to SPRINKLER TALK FORUM - You Got Questions, We've Got Answers. If this is your first visit here, please read the Help. It explains how this page works. You must be registered before you can use all the page's features. Please use the registration form, to register here or read more information about the registration process. If you are already registered, please login here.


Starting Member


Sunday, October 8th 2023, 7:05am

Oscillating, slow to turn off valve. Need help.

Hi -

My residential sprinkler system consists of 6 zones. 4 of these zones use rotary Hunter valves. One of these 4 rotary head zones has an issue that I do not know how to solve. This problem zone valve struggles to shut off completely. In fact, it oscillates for 2-3 seconds before completely shutting off. I am able to visibly see water trickling out of some of the heads during this time. There is also an audible thumping sound until the valve closes completely.

I had always suspected a faulty valve was the issue because I was experiencing water leakage around the valve area. I ended up repairing the cracked manifold associated with the troubled valve. I also replaced this valve with a new valve. Unfortunately, this did not solve my oscillating, slow to turn off issue. I would appreciate some advice how to solve this problem. As mentioned, the problem is only at this 1 zone and I've replaced the valve and repaired the cracked manifold.




Posts: 1,520

Location: USA


Sunday, October 8th 2023, 10:06am

Since you've changed the valve and you have the exact same symptoms, then there wasn't a problem with the original valve.
But with that said, if you installed the exact same model valve that you had before, it's having the same issue as the previous valve. There's probably too much flow going through the valve.
When it shuts off you're getting water hammer. That could be what cracked the pipe. And it will happen again if you don't fix it.
Is this your valve? You could try fiddling with the flow control to see if you can make it some better.
But if there's room, maybe install a different model valve. Like this one
If there's a way to lower the water demand on the zone in question, that would help a lot. Smaller nozzles or less heads would help.
Did you open the bleeder screw after installing the new valve? You need to get the air that's trapped inside out. That can cause a problem as well.



Sunday, October 8th 2023, 2:55pm

Thanks for the response. Tomorrow I will play with the valve as you suggest.
The Hunter valve you pointed out is indeed the ones I've used. However, I have the same valves in all of the zones and if there is a pressure issue, why don't I see this phenomena with any of the other zones. Just the zone in question will not close completely, so this confuses me. To me, the water hammer theory doesn't seem to be the issue here otherwise why wouldn't it occur for all zones?It is true that I did not bleed the replaced valve after replacing, so maybe air is still trapped in the valve. I'll look at that.
Does the flow control feature of the valve effect the input/output or both?
I will try to report back tomorrow.
Take care

Rate this thread