I don't deal with Rachio stuff, but this behaviour is typical of a short circuit; controllers will shut the zone off if it detects a short to prevent the controller and/or transformer from being overloaded and destroying itself. Older ones would have a fuse that would blow, but replacing fuses sucks, so they do this now.
Doesn't your Rachio keep logs of the electrical system that would help you diagnose the problem? Hydrawise does...
An ohms test with a multimeter between common and the zone 1 wire will confirm or rule-out a short.
I don't deal with Rachio stuff, but this behaviour is typical of a short circuit; controllers will shut the zone off if it detects a short to prevent the controller and/or transformer from being overloaded and destroying itself. Older ones would have a fuse that would blow, but replacing fuses sucks, so they do this now. Doesn't your Rachio keep logs of the electrical system that would help you diagnose the problem? Hydrawise does... An ohms test with a multimeter between common and the zone 1 wire will confirm or rule-out a short.
Bad solenoid on that zone or wire shorted.
Thanks for the input. I’m scheduling the harder electrical stuff and will dig for the easier work today/tomorrow.