Hi, I was wondering if someone can help answer if there is suppose to be water flowing through the pvc pipes that are beyond the control valve when the sprinklers are in the off position? i.e. - if I unscrew the whole sprinkler head that is attached to the pipe - should I still water flowing through the pipes? Or is the function of the valve to shut off all water from flowing beyond it when the sprinklers are off. Thanks, Bob