SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

Hi All,

I have a pretty old system, but until now has been working pretty well. 7 zones. 1-4 work as intended. When zone 5 starts, zone 6 also comes on. When zone 6 starts, zone 5 stays on. When zone 7 comes around, 5 & 6 shut off, and 7 runs as intended.

I've read a forum entry or two regarding this problem. I've seen a ground/common wire problem in one thread. About the only thing different I did was put a volt meter on the terminals at the control box. With zone 5 selected to run, zone 6 is also live with 25v. Ditto when zone 6 selected, zone 5 is live also.

Now, I'm not sure where to go. Are there any other tests to see if the controller is bad? I guess I could tinker with swapping 5 & 6 to terminals 3 & 4 and see if I see the same problem. That might isolate it to the controller or something somewhere at the valves. I have not replaced any wire connectors at the valves yet, just trying to figure the best place to start.

Thanks!

Yeah, when I unhooked zone 6 and turned on zone 5, zone 6 seems to be floating at 2-3v or something -- the same as unused terminals on the controller. Same when unhooking 5, and turning on 6. I'm guessing that means the controller is OK.

Nothing has changed and has worked for years til now, so they are not wired together. Maybe the 5 & 6 live wires are exposed to each other somewhere then. I do have one extra unused wire that maybe I'll try.

Well, I think I did a boo-boo during my attempted fix. I tried the extra wire on zone 6. So, I unhooked valve 6. The extra wire was connected to the common, so I unhooked that, and connected to zone 6. Unfortunately, I connected the old zone 6 wire to the common also -- like the extra wire had been. I hooked the unused wire up to 6 at the controller. I ran thru stations 1-4 and worked as intended. When zone 5 came on, nothing happened. I had 0v at the terminal. Same with 6, same with 7 when I went there. Then went back to 1-4 and now had 0v on all of them too. So, if the theory was 5&6 live wires were exposed to each other, could I have cooked the controller when zone 5 was activated -- the controller was trying to drive 5, while the old 6 wire was connected to common, and we think 5&old6 are shorted somewhere??? The fuse is good -- I'm getting 28v across that. I subsequently unhooked the old 6 from the common, but still get 0v on all stations.

I suppose I could try a new controller and take it back

Thanks for your help. Back to normal. Fuse was the problem, and the extra wire solved the initial problem. 1-7 running as intended! Now to change a bunch of heads....