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i still say there's a shut off somewhere that's not fully open

That's pretty much the only time I ever get pulsating from a valve. I service 1000's of systems . Start checking your crawl space

Ok this is really puzzling. Now the 4th valve just turned on and it's not pulsating, which is good, but why is the 3rd one still doing it?

welp that didn't last long. When the valve started tonight as scheduled, the pulsating started again

So now it's not a solenoid problem nor a diaphragm. Then what could it be?

valve diaphragms are part of the equation, when it comes to this sort of oscillation - changing them can be a cure - sometimes

Looks like I've fixed the problem...hopefully it doesnt come back.

What I did was I tried switching the solenoids around from the zones that are working properly and that didn't seem to do the trick. So I placed the solenoids back to where they were and I opened up the diaphragms and swapped those around as well. So like, zone 1 & 2 are the good ones and zone 3 & 4 were the bad ones. I swapped 1 & 3 around and 2 & 4. And that did the trick! no more pulsating on all the valves!

What I noticed is that when I was removing the diaphragms from the bad ones that they just easily lifted off, while the 2 good ones had a little resistance to them like they were air tight or sucked into the valve. So when I was switching them around, I gave them all a push into the valves and really tightened up the covers.

So far none of the valves are pulsating. I'll update in a few days if this problem happens again.

Maybe you have to reduce the pressure upstream of the system

I forgot to add in that I have 2 of these installed




one on each valve. It's a drip manifold that splits the connection into 8.

on one of the valves, the pressure was so great that it blew out 2 of the unused/closed connections on the manifold. So I figured maybe the pressure is too strong, so I installed a pressure regulator on both of them and now that's fixed, but the pulsating still occurs after the pressure regulator was installed.

fairly new. I installed them maybe 2-3 months ago but haven't fully tried them since a week ago because I've been working on other things in the frontyard.

All four of the valves are rainbird.

Yeah I find it odd as well and it only happens with the ones that are drip irrigation.

How old is the system and what kind of valve?

It's possible, I just dealt with one like that on friday.

But to have both go out at the same time seems odd.

But when I open the valve all the way manually, there is no pulsating. Could it be the solenoids not opening all the way?