Valves stuck on

[davefromnh]

Folks:

I am running Toro 1" valves. Last year, one of them refused to turn off, once it was activated by the timer. It was not a necessary zone, and I have been busy rebuilding the yard, post-pool installation (think "Beiruit"). Now however, another valve has done the same thing.

I read prior threads on this issue. It seems like insufficient pressure or sand is to blame in many cases. Pressure is fine, so I wonder is I need to remove the solonoids???? These valves will be a nightmare to remove, if necessary. However, I have good access from above. Should I simply remove the two screws, and pull the solonoid? Is there anything in particular that I should be looking for? Should I replace the solonoid, or just flush the area? (These valves are 3-4 years old).

Any thoughts would be appreciated.

[davefromnh]

I had a talk with the Toro folks, who suggested disassembling the whole thing, and inspecting for debris or a torn diaphragm. They then told me to reopen the water supply valve and flush the body, and reassemble. Did so. In the course, found a very small stone wedged in the diaphragm. Unclear whether it was the stone, but it appears to be working properly now.

[Brickman]

I would be willing to bet good money on the stone. Sand will do it, so I would imagine a stone could too.

I do as much matching exact valves as I can. Then pull the screws out of the new one and the old one. Put the new top on the old body and you have a new valve. After all the bottom part doesn't have working parts that I have ever seen. One thing you have to inspect when changing them is that the mating surfaces on the valve body are in good shape, no burs or cuts. That can cause a valve to hold open to.

Yes you are right, some valves would be a mother b***h to change out. I see it all the time.