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Friday, August 26th 2011, 12:40pm

One zone is on anytime the Controller is plugged in.

Please help! I'm far from a sprinkler guru, so any help would be appreciated. I've had the main water turned on to our sprinkler system all summer, but haven't run the sprinklers. I decided to run them this week so plugged in the main controller to the system. Zone 8 (of 12) came on even though it's timer is shut off. I took the solenoid out and tested it. The plunger sucks in when I plug in the controller like it's supposed to. Unfortunately, it stays on anytime the controller is plugged in. The other zones run like they should, but with less pressure since zone 8 is always on. I've seen posts talking about zones staying on because of some blockage in the diaphram, but if that were the case here, zone 8 would be on anytime the water is turned on to the system, but it's not. The only time it comes on is when the main system is plugged into power. BTW, it's a Toro system.
Any ideas?


Supreme Member

Posts: 5,331

Location: Metro NYC


Friday, August 26th 2011, 1:04pm

Time for a new controller


Friday, August 26th 2011, 1:12pm

How certain are you Wet Boots that the controller is shot? Because I had a Toro controller, do I have to replace it with a Toro controller or will any controller run the sprinklers?


Supreme Member

Posts: 5,331

Location: Metro NYC


Friday, August 26th 2011, 4:30pm

a constantly-on zone is a fault on the main circuit board - if you had a computer that was similarly faulty, you could have a repair shop install a new motherboard - doesn't work that way with controllers. On the best "pro" equipment, one can swap out the front panel, with the mainboard inside. On consumer equipment bought at Home Depot, you just trash it and get a new controller.

And obviously, if you have an unused zone, switch over to it and let the faulty zone stay unconnected to the system.



Posts: 2,403

Location: USA


Friday, August 26th 2011, 11:08pm

I saw this happen once on a Toro controller and it was a bad module.

Now I'm second guessing myself. This was 15 years ago. It was a Toro and it was a module but I'm not sure if it was on all the time or if it just came on when any valve came on.


Supreme Member

Posts: 493

Location: Seattle


Friday, August 26th 2011, 11:53pm

I've had several Rain bird ESPM's send constant power to valves before when plugged in.

don't know if it was a controller with/ without the mv error strap though


Supreme Member

Posts: 5,331

Location: Metro NYC


Saturday, August 27th 2011, 4:55am

As noted, modular controllers allow for the possibility of a faulty module, and modules can be replaced on their own.

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