Got sent out to a apartment complex that has valves that wont come on. My boss already told me it was going to a wire locate. So out of seven zones the first three at the controller have continuity, the last four, nothing, open circuit. So I use my bosses Greenlee 521 to trace the common. I know where the first and last valve are and two in between, so two m.i.a. Well when I saw the last four on the controller had no continuity I kinda knew it was a common wire issue, nicked, bad splice, etc. I tried hooking the ground clamp to a zone wire and the other lead on the common and trace a zone but couldnt isolate one solenoid from the others reliably. Spent three hours getting this far. We also have one of those Greenlee "toners" but im not sure if that is the right tool for this. Obviously I don't have a lot of experience locating. Any help/ideas/suggestions much appreciated.