Attached are the wiring for my old Hunter SRC and my new Gen 3. In the wiring picture from the Hunter, the three wires to the far left were for the power supply (two farthest right) and a remote control connection. Connecting the new control was a breeze through WiFi but I cannot get the unit to raise any of my sprinklers to test them as part of the setup. Help! 
Never mind; figured it out! Out of frustration I started trying random zones and discovered, for some reason, that my zones start on 5 using the Rachio… instead of 1. Weird, hunh? My nine zones are somehow sandwiched right in the middle of the available zones although they’re plugged into the correct ports on the head unit. Seems to work, but does that mean there’s some kind of defect? Actually… looking at the unit again, “Zone 1” is above the 5th port… the first four ports don’t have labels?!? My unit doesn’t have all 16 zones properly labeled/printed on the plastic (at least when compared to the instructions)! Could this be an issue???
@RobPlusTen - Rachio has a special unit they sell through Costco that is just 12 terminals (instead of 16). It looks like you have the Costco version
Great point! I ordered this however from Amazon directly from Rachio… maybe Rachio sent me the wrong one???
Woah! How weird. Pinging our ops/sales team to look into this!
- Oddly enough, the labeling or numbers printed on the face cover correspond to the 12 numbers “offset” on the unit itself. This basically makes the first four “blank”, both on the unit and faceplate. Once it got everything up and running, I couldn’t be more impressed with the app, interface and functionality of it… I was telling my wife that it told me watering has been postponed automatically due to recent and expected rain! LOL. This weird quirk in the unit is my only concern. And for the record, the box I received was still sealed with the factory sticker.
SO strange! Thank you for sharing more information. Very happy to hear that you’re loving Rachio 
Keep us posted if anything about the system starts behaving oddly - sounds like it should still work just fine with the weird offset zones, but want to keep an eye on it just in case!!
I think you got that rare collector’s edition!