Found a mystery wire during R3 install

Bought this house s couple years ago… No information turned over regarding the irrigation system. Been using the 5 zones (29 sprinklers) in manual mode since moving in without issue.

Swapping out for a Rachio 3 just now, found this brown wire just hanging out. I connected it to a zone and nothing happened. Could it be a master valve? If so, how do I test it? If it’s not, will it hurt the Rachio to wire it in?

Thanks for the help!

Hi Avery,

It is unlikely to be related to something important (like master valve), since you were able to water other zones without it. You can use a multi meter and check resistance between that wire and commons, but frankly the test you’ve tried (simply plugging it in and activating the relevant zone) is just as good.

I would mark it as unused (spare) and leave it be. If you can find your valve box and take a picture inside, the mystery of the extra wire can likely be solved.