OT: Sprinkler valve question

Did you change anything? Did the feed water pressure change? Did you add or change any heads or bubblers?

No, absolutely nothing was changed. Unless a sprinkler head became plugged but that's hard to find now because the last times I tried to start it it'll rattle every time and then not develop much discharge pressure.

It might mean a trip underneath the house. Oh, how I dread those. Plus changing out those valves is a bear because the mfgs screwed up the threads. One side should have been CCW thread but they didn't do that.

Check for broken/leaking pipes. Probably air entering the system.

Sounds like a borderline water-hammer type oscillation. Does the system have those damping tube tee things?

Are the pipes tied down good? If they have any play, like right angle bends that can flex a little, that increases the likelyhood of oscillations.

I'm sure glad that electricity in wires doesn't do this.

Before the valve it's all ok, there are two others (very old brass types from the good old days) at the same location which work fine. I don't know how air could get in there.

Could be a mass-spring oscillation in the solenoid valve itself, if the drive is too weak to hold the valve all the way off.

Cheers

Phil Hobbs

Yes, it almost sounds like that. But why now and not all the years before? This valve has been in there for 3-4 years or so, and no changes to the system afterwards.

Maybe the new valves are just not that good anymore and break fast.

Nope. This is all 1970 stuff but at least it has 1" pipes in that section. The house itself is 3/4".

Come to think of it, there is one such section tapping off at the point where the water main enters the house. The valves are under the house about 15 ft farther inland.

Actually, switchers can do that. But only for a few seconds, after that there is a loud bang and all kinds of stuff flies about.

Depending on the type of valve, some of them actually open and close the valve using primarily the water pressure. I vaguely recall a little teeny vent hole that can get plugged and cause all kinds of grief. Any tent spider webs visible?

I haven't done this kind of work myself in years... I'm in trickle down economy mode ;-)

Though my yard guy may have out-smart-mouthed himself. On Tuesday he indicated an inclination toward more stimulus. I've just about decided to cut off his trickle :-) ...Jim Thompson

These things are pilot-operated servo valves. A needle with a groove in it passes through a hole in a rubber diaphragm. The needle is operated by the solenoid plunger. It allows water to flow to one side or the other of the diaphragm, pushing it to plug the inlet port or open it. The same mechanism is used in toilet valves, washing machine fill valves, etc. When the hole in the diaphragm wears out, you get these rattling effects, where the pressure only partially opens the diaphragm and it flaps like blowing on a wind instrument mouthpiece.

It is possible the crud in the water has partially clogged the passage in the valve. Sometimes a cleaning will help, for a while. it seems like it might be a good idea to move the valves to a more accessible location, as these will need maintenance periodically.

Jon

Axial motion of the pipe seems to create new water-hammer modes. You might try strapping the noisy pipe down to something, or dumping a blob of concrete onto it near the middle.

Just tried, even shut off that section. No change whatsoever :-(

I think that fairly new valve is already busted.

That would be sad. Then I'd probably buy a new valve of a different brand. The other ones are over 40 years old and fine. This one isn't even 5 years old.

Very tough at that spot. They put these valves under the house and fan out from there like a spider. The south side of the house I was able re-plumb, those are all outdoors now.

Getting there is the big challenge. Lots of crawling.

No pun intended but you might actually get stuck on the way to that valve :-)

Ouch ...

Well, it's my professional opinion that you should change the valve. Where do I send the invoice?

I don't know. I fold up pretty good and fit inside kitchen cabinets.

It's my duty ;-) ...Jim Thompson

My accountant is in that position. When I started with him about 10 years ago his charge was $125. Last year he charged $400. and then $150 for a 45 min 1040X. My income hasn't tripled nor has the complication of my tax forms. I'm moving to someone else next year. I know $400 is not outrageous, but I think I think he figures he can add more each year without consequence. I made the mistake of mowing the lawn earlier this year, now my wife thinks it's my job! Tuesday I mowed 3/4 of the lawn when the drive belt broke, so a 50 minute job turned into 4 hrs. Today I got out the weed whip and was almost finished when it quit. I had to repair the power cord. I missed my nap today :-( Mikek

But your first advice didn't do the trick, I bumped my elbow reaching down for the valve, and now I need to find a personal injury lawyer :-)

Luckily I had a surprise design review and now it's too late to crawl down there. Unfortunately tomorrow there may not be such a good excuse.

Who makes it? Asco? If so, we have some experience with those ;)

THey have a booster port valve which is what actually does the opening. it supplies a low volume water source that forces the main actuator on.

So the solenoid does not need to be that large, they just don't open real fast.

There are two things that go wrong that I can think of off the top of my head.

1. You get crap in the valve and it screws up the booster primary port that supplies the main port or, that needle is getting stuck.
2. Many of them have a diaphragm that gets a pin hole in it, that will cause the main valve to chatter because it can't hold the water from the booster port. The hole usually opens as the diaphragm flexes. That usually can be fixed with a rebuild kit.

Do you have lots of lime or iron in your water?

Jamie