Sounds more like a wiring problem than a interference problem.Nothing stuck on, but there were several alarms showing on the controller.
They have checked voltage, etc. at the valves and it's ok.
I suppose I need advice from someone who's familiar with the Toro system.
The problem seems to be intermittent communication between the controller and the decoders.
Nobody can figure out what's causing it. The current theory is interference from crossing a power line too closely. Is that a plausible explanation? They used the specified wire but it's not shielded.
The controller has diagnostics, but when you run them, different stations show a fault on different diagnostic runs.
The controller puts out 38 volts BTW. Anything between 12 and 38 volts is acceptable.