Sprinkler valve not closing completely

Yesterday I turned on my sprinkler system for the first time to test
it out. This morning I noticed one of my pop up heads was oozing out
water. When I checked the sprinkler valve, I could hear water going
through it. I shut off the main and the water stopped running, so
obviously the valve is not closing. I believe the valve is made by
KIT ? Any ideas where to start? I can take off the solenoid valve and
I see what looks like a plunger with a spring, but not sure what the
problem could be.

It could just have a small stone or plastic in the pipe. Open and
close the valve a few times and see if it will flush out.

When a new system comes on line, there are always curlie Q pieces of
plastic from the cutting process. We have t flush them out of our
fire engine all the time.

How old are the valves? Did you have a freeze this past winter?

The rubber diaphragm(sp) becomes weak over time and water leaks into
the zone. You should be able to find a kit to rebuild the valve or
just replace it.

I don't know how old the valve is. Also the valve is made by HIT.