Zone Faulting intermittently (but I can force it to work)


A bit of a weird problem. For a couple of weeks, when I run my sprinkler system, I get an error that either the master valve or zone 4 has vaulted. I replaced the solenoid on the master valve, and all my other zones work correctly, so I believe that zone 4 is at fault for some reason. I couldn’t find the valve for the zone so I tried a few other troubleshooting steps:

  1. I Tried moving the connection from zone 4 to zone 10 and running zone 10 (an unused zone). Same fault on Zone 10 that i’d been getting

  2. Here’s where it got a little weird. I plugged zone 4’s wire directly into the +24V wire. When I do this two things happen: A) Zone 4 runs whenever ANY zone runs B) Zone 4 runs fine and the solenoid operates. When i plug zone 4’s wire back into zone 4, the zone works fine intermittently, but then faults out again then doesn’t work at all after it faults.

So right now, on the days I have my sprinklers scheduled, I run out and re-wire it, run zone 4 by itself manually, then rewire it back to normal and let the sprinkler schedule run normally.

My first thought was that I had a bad solenoid on zone 4, but I can’t wrap my head around why plugging directly into the +24V line would cause the zone to function. It makes me concerned I have a bad controller?