I just bought a new Orbit rain sensor. The old one was never connected and dry rotted so I bought new.
There are only 5 wires run between the controller and the valves; common and 3 zones leaving 1 wire unused.
I connected the rain sensor to the free wire and the common and the connected the free wire to S1.
It seems to detect the sensor but it is constantly flip flopping, activated/deactivated every few seconds.
There is zero rain so the sensor is not wet.
Oh, I have a Rachio3 which I just got maybe a week ago so that’s new too
Any ideas?