I just purchased a house.
When I opened the main water line valve to my sprinkler system several heads opened up and a part of the yard was getting watered. However I couldn't turn those heads off with the timer/controller so I turned the main water line valve off. Eventually I realized that I had a valve box that provided access to an array of valves (manifold?). Here is a picture labeled 1,2,3,4. 2 and 3 have manual shut-offs and I determined that 3 hadn't been shut all the way an that is why some heads started spewing water when I opened the main valve. Next I figured that I was supposed to open these manually, valves 2 and 3 that is. However when I open #2 up to it starts to vibrate and the manifold starts to shudder and make a hammering sound. Can anybody set me straight on what is going on . Also why are 1 and 4 different from 2 and 3. A lesson in sprinkler valvology would be greatly appreciated.
Thank You very much,
Aitch