Couple of questions. Have you checked the orientation of the valve (ie is it installed with the flow arrow pointing the proper direction). Second, does the system have a master valve? If the system has a master valve, then that explains why it goes off with the system off. How long has the system run before the problems were found? Did valve 3 start closed, open when supposed to and then never shut off or did it open as soon as you put water to the system?