Thanks Gene. That is a great thought. I’ll look into that. Stupid question, but would it be visibly noticeable if a valve were stuck open?
Unfortunately, when I open some of the valve boxes, I see what looks like 18 gauge, colored, six (?) wire cable and some heavier gauge red and white wire. At the controller, all of the wires are the red larger gauge wire with the common, larger gauge white.
I have a Klein toner that may work to at least trace the “M” wire to its’ destination. We are in central Texas, so the lines are not very deep. Most of the nuts and bolts of irrigation install are new to me, so figuring out the whole of the system is going to take some time.