`Just installed a new Rachio after using a Hunter SRC. I also have a rain bird rain sensor. The irrigation guy who originally installed my system spliced the rain bird wiring so that the black cable is connected to the white common cable, back near my valves. The red wire was connected to a separate yellow wire to my controller.
So at the controller end I only have a yellow wire from the rain sensor and the main white common wire.
I presume this is not enough to wire the rain sensor to Ranchio?
I've tried it by putting the yellow wire in to S1 but I get a continual activated and then deactivated every minute.
(Note the white is connected to the main C for the zones and all zones water correctly)