I have an underground sprinkler system. A few days ago a valve got stuck "on" with a loudly buzzing solenoid. I replaced the entire valve with a new one and wired it in, tested, and all was well:
Today the zone whose valve I replaced randomly turned on even though the program is not set for this time. Turning the system from AUTO (schedule) to OFF successfully closed the valve (and stopped the sprinklers), then setting it back to AUTO kept the valve off… for now.
Typically when a valve is stuck on there's either debris in the line or the solenoid went bad. I ensured both are solved with my replacement valve. So, given that the new valve is still exhibiting quirky behaviour, what could possibly be going on? It must be receiving power to be on at this point so could the controller be going bad? I've had the controller since we moved in 3+ years ago and it has worked perfectly.
Best Answer
Today the valve went back on at 12:55pm local time. Also, while it was on, it did show valve 2 active on the display and the 25 minute countdown timer that I normally use for it, so this is 100% the controller.
I could not find any program setting or schedule that had only valve 2 going on at 12:55pm (which also is impossible according to the scheduler of the controller which works only in 15 minute intervals), so I assumed it was some kind of weird or bad programming state, especially since I finished replacing and rewiring the valve around 12:55pm on Sunday (though this may be a coincidence).
Earlier today I did a factory reset and re-programmed my nightly schedule from scratch. We'll see tomorrow whether or not that worked for sure. ;)
EDIT: it worked! Controller was in a weird state, a factory reset fixed it.