Help! No C wire?

Hi I’m trying to upgrade from a Rain Dial to rachio. I’m a little confused bc I don’t see any C wire and there are two grounds (two white wires).

Also I’m not too sure the wires in the 24vac needs to be plugged in from reading other posts in this forum. Confirmation as to how to handle these thinker red and yellow wires would be greatly appreciated.

Thank you from an auto sprinkler newbie!

It looks like the white wires are the common wires. Just use the supplied transformer with the barrel connector connected to the Rachio. No other power is used.

I am a true newbie to all this… should I just put the white wires to the C terminals? Do you think it’s ok to just cap off the big red and yellow wires that go off to the 24VAC on the rain dial?

thank you for your help

@SprinklerNewbie - @Thomas_Lerman has it correct.

  1. Correct, but the two white wires into the Rachio C terminals. One can put one wire in each C terminal as there are two in most Rachio models or put them both in one terminal.

  2. You can cap off the red and yellow wires going to the 24 VAC terminals. Or you may be able to trace them back to a transformer or plug somewhere. They could be internal to the Rain Dial when you remove the box and its power.

Welcome to the community.


The inside of that Rain Dial housing looks like a habitat at an entomology lab. :spider:

Welcome @SprinklerNewbie!


Pretty sure it was the breeding ground for a new species of spider-cricket.

1 Like