Accommodate Rain Bird RSDBEX rain sensor?

My Rain Bird controller, soon to be replaced with a Rachio 3, has a Rain Bird RSDBEX rain sensor.

Should I bother wiring that to the S1 and S2 terminals of the Rachio 3?

You have at least a couple of choices:

  1. Do not hook up the rain sensor and exclusively make use of the weather stations that likely exists in the area.
  2. Hook up the sensor and use the very local information as to whether it is raining or not.

Deciding is obviously up to you. Part of it may depend on how close the weather stations are to you and how accurately they compare to reality for your yard.

I found the manual (link is below) and appears to have two way to hook it up (if you so choose, but between these two, I would do the first option):

  1. The old controller uses the SENSOR terminals which is for one sensor. The Rachio uses S1 and S2 terminals, which are for two sensors. So, you would use one wire going to S1 and the other going to power. According to Rachio 3 and Rainbird RSD-BEx - Accessories & Sensors / Rain Sensors - Rachio Community, you would hook the other to -24V.
  2. Between the common terminal and all of the commons used for the valves

man_RSD.pdf (

P.S. I made a correction to my original post.

@Thomas_Lerman - for what it is worth I don’t recommend option 2 (for wiring the rain sensor), I have seen people with older controllers that have this configuration blame Rachio for not watering when the sensor was the root issue. Rachio will think it is watering when the rain sensor is blocking it - defeating all the smarts of an intelligent sprinkler controller like Rachio.

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Yeah, if I did not make it clear, I would not recommend it either for the same reasons. Thank you.

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