I have an irrigation system controlled by a Rainbird ESP Modular controller. After a T-storm, all zones on one module are on whether the controller is turned on or not. It just needs to have power to the timer. Whenever the timer is powered, I get 24 V AC to all four zones of the first module. All zones work properly when the system is powered down and the solenoid valves are opened manually.

Is this likely to be the module or the timer? Any way to test it?

Thanks anyone!