Is Rachio gonna work for me!

I currently have a very old controller - Richdel 500S. I have three white control wires and eleven zone wires. Can I use the Rachio IRO 12 zone - how would I connect the three white control wires? It looks like it only has two white control ports.

@scotatl Can you post a picture of your old device and wires? This will help the support team. Thanks!

Or if you are not comfortable doing that in the forum, send the pictures and description to



Will do - Thanks

@scotatl Thanks for the pictures, I’ve forwarded to @emil and the support team.

On first pass, I’m pretty sure I’ve seen this unit before. It definitely needs to go into some museum :wink:


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@franz, we gotta get a trophy case for these!

@scotatl, where do you fine this rare gem?! The Richdel 500 was ahead of it’s time…not so much today :wink:

This controller is 110% compatible with the Iro. Please use this wiring guide to cross reference.

Do you plan on keeping the wirenuts below the controller or cleaning those up?

Best, Emil

@franz @emil You should have a trade in program for gems like these!! :joy:

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I do plan to remove the wire nut collection - not sure why the previous owner spliced the wires.
I looked over the wiring guide but still not sure about my three control wires - the Iro looks like it has two control slots, can I double up on one slot? Thanks!

@scotatl, thanks for the feedback.

I’m not sure either. It amazes me some of the wiring photos we see. @franz keeps a special collection :wink:

I believe you might be referring to the common (white) terminals? If so, than yes, you can double up 2 of the 3 wires into one of these.

@MaverickC2, love the idea! Perhaps a controller recycling program…

Why, yes I do.

Aw, shucks! I just checked out the tumblr link, @franz. That’s one of my veggie beds in the photos. Thanks to all the hard work done by you and the rest of the team, the Iro makes it a breeze to keep it all properly watered. At summer’s end, we harvested corn, tomatoes, and tomatillos–enough to make and can salsa and pasta sauce.

This spring, we added a fifth fruit tree, a potato patch and some blackberries and another veggie box and it was a snap to add these to the Iro schedule.


Fantastic! Great we can help nurture the garden, happy growing season!

Oh snap!

We love this, and hoping to build this out.