Recently installed a Rachio 2nd generation to replace my Rain Bird ESP-6TM controller. My home has a rain sensor outside attached near the roof, but the old controller didn't have any connectors for a rain sensor, and the cable coming out of the wall going to the old controller also only had 4 wires which were connected to "COM", and 1,2 & 3 so I'm assuming these are common and 3 zones.
I've got these connected to the same connections on the Rachio controller, and everything appears to be working fine with starting the sprinklers in each zone (tested using the manual start, haven't tried the scheduled jobs yet).
There were also 3 wires connected from the power adapter from the wall power outlet to the old controller, which do not appear to have anything to do with the rain sensor, and I think they can be safely ignored.
The cable from the rain sensor outside drops into a PVC pipe which runs down the outside of the house and into the ground, so I'm not sure exactly where it leads to. However, I'm assuming that as the old controller did not have connectors for a rain sensor, it's using the alternative way of wiring where it hooks into using the common wire instead.
We had a short thunderstorm today and while it was pouring down, I tried to manually start the sprinklers in zone 1 for a couple of minutes using the Rachio app to test the rain sensor and they began running immediately for the 2 minute duration before turning off.
Does this mean that the rain sensor is not connected / not working? I would've thought that if my assumption is correct about this being hard wired into the common connector is correct, then when the rain sensor is tripped, even a manual start of the zones should not work?