Random Blue Wire

Getting ready to install my new Rachio 16ZULW-C 16 Zone: 3rd Generation Smart Sprinkler Controller and doing some research before I get into it.

Opened up the existing Hunter Pro-C controller to these lovely terminated terminals…and a random blue wire floating in the box. Does anyone have an idea of what this blue wire could be that isn’t currently connected to anything?

Maybe a spare zone wire that is ran, but not connected to anything?

Would it be some sort of special zone control though? They used red wire for all eight other zones so I just don’t understand the truly random blue wire.

Since it is not hooked up, it does not seem like any special zone control. I am not really sure what that would be and it seems like it could be any number of things.

It looks like the power & sensor are exiting the box in their own location and the pump/master valve with all the zones are going through the PVC. I would probably check for a blue wire in the sprinkler boxes, etc.