Seeking wiring help on Irritrol Rain Dial to R3

This is a picture of the existing wiring from RD-1200. I’m stumped on the mapping of the two white wires into EARTH GROUND. Thank you!

Just to double check some things, I took a look at the manual at 373-0538V_d.ashx (

I do not think you will connect the Earth Ground. I believe that is normally used just to ground out the box and electronics when the transformer is inside the housing.

It looks like you have an easy conversion. Just for others’ information if they need to go the same thing (it sounds like you have it figured out):

Top row, left-to-right:

  • Earth Ground → do not connect
  • Zone 7-12 → Zone 7-12
  • VC (valve common) → C
  • 24VAC → do not connect, instead use Rachio supply power adapter

Bottom row, left-to-right:

  • Zone 1-6 → Zone 1-6
  • MV/Pump → M (configure in app)
  • Sensor → it seems usually, people do not connect. Can always change mind later

Thanks. As you can see from the picture of the legacy controller wiring, VC (valve common) has no wire going in on the legacy controller. The same with MV/Pump - it’s bare.

This will leave only Zone 1-11 wires mapping to Rachio, with no wire to C, and no wire to M. Will this work?

I noticed most of the empty terminals (including the sensor terminals do not exist on that model. I did, however, miss that the VC did not have any wires going to it. I would have to guess that someone actually hooked the VC to Earth Ground for some reason. With all that, I would guess that the two wires going to Earth Ground should have been hooked to VC, so they would be put on Rachio’s ‘C’. If your model has multiple C, it does not matter which they get hooked to. So, hook one to a convenient ‘C’ and the other to another ‘C’. I believe the one of the white wires is the C for all the smaller colored wires and the other might be for the thicker red wires. You can always double check by hooking up one wire and running each zone to see what comes on. If any of the zones do not come on, hook the other one up and run each zone again. Sorry for missing that in the picture.

Cool. Will try that. Thank you!

No problem, please let us know how it goes