Wiring Help - What is this thing?

I’m replacing a Rain Bird ESP Modular controller with the Rachio 3. The Rain Bird had the valve terminals 1 and 3 connected to the item in the picture.

That thing was then connected to the #3 valve control wire. My questions are:

  • What is this thing?
  • How should I wire my Rachio to deal with it? Should I leave it connected to the #3 wire and then connect it to terminals 1 and 3 on the Rachio?

There is a post showing similar devices, Rain Bird ESP-me Wiring Help and refers to a master valve but I’m not sure if or how it applies to my setup. I just moved in and know very little about the sprinkler system other than what is visible above ground.

Thanks in advance!

That is part of an add-a-zone module kit. You will need it! That splits one of your wires to two out in the field. There is another module in a valve box out in the yard somewhere. You’ll need to remember which wire the orange was connected to at the controller.

What this means is, a wire went bad and the last irrigator couldn’t find the break and adding a new wire was too costly or a zone valve was added and they used this instead of running a new wire.

Here is a link where you can learn about it: Add-A-Zone info

Welcome to the neighborhood!

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Or to could be as simple as they where running two zones as one, or they actually had a master valve. I’d hook them up separately and see what happens and if you have any zones that aren’t working when you do. Do you already know what sprinklers where connected to those two wires?