Plumbing and Piping - sprinkler system valve question

I moved into a house that had an existing sprinkler system. I find that the first zone is messed up some how. I have been twisting the value connected to the zone to understand what is happening. When it is open the valve manually the zone runs with the appropriate amount of water pressure however when the timer ends on that zone the water does not shut off. If I turn the valve the other way even a little bit the zone does not have enough pressure to run properly. And the only way to full stop that zone from running is to turn the system completely off or manually close off the valve. Can someone tell me what might be going on? Thanks.:confused:

Exactly which valve are you talking about? The one with the solenoid?

That valve is not an off/on valve. It is an on/auto valve. What you call turning off is actually turning it to auto. (I think)

It sounds like you need to clean the solenoid valve on that zone. Or maybe replace it.