Rainbird ESP-Me to Rachio 3

Trying to figure out the wiring on the Rainbird
I have a rain sensor and a Hunter relay for pump. I am attaching photos
Seems like a few connections doubled up
Can you help me to map 1 - 1 to the Rachio 3?

Should I not bother with the rain sensor?

@bruce_tampa - piece of cake. Don’t worry about the doubled up connections.

Easy pieces are:
Rainbird -> Rachio
MV -> M
1 -> 1
2-> 2
3 -> 3
4 -> 4
5 -> 5
6 -> 6
7 - > 7

For the three wires on the COM terminal there are two choices:

a) wire the three wires together with a fourth (short pig tail) and connect the short pigtail to a Rachio C terminal.

b) if one is buying the 16 zone Rachio there are four C terminals, so one can place an individual wire in the C terminals without running out of terminals (the 8 zone only has two C terminals - so I’d combine some wires).

The rain sensor is optional - belts and suspenders.

Here is my guess on that - depending on the model (https://support.rachio.com/hc/en-us/articles/115010379147-Rachio-compatibility-with-Irritrol-Wireless-Rain-Sensor)

One red 24VAC to VAC-
Other red 24 VAC to VAC+
Brown Sens to S1
White Sens to VAC-

Ignore the orange wires in the 24VAC and the green wire in the GND terminals. Be sure to trace back the gray wire that supplies the 120 VAC to the Rainbird and disconnect that wire - unless one is going to use that wire to supply a Rachio external enclosure.


Wow thanks!
Sorry in my rush to post of forgot details
Rachio 3 16 zone
Rachio outdoor enclosure

The rainbird seems to have a transformer so I assume tracing back the wire will result in it being at that transformer… which will be removed when I remove the rainbird.

Are “bells and suspenders” a good thing? :slight_smile: is it what people use or just don’t bother since the weather is accurate from Rachio?

Ok actually I think you answered everything already but posting this more for clarification than anything.


@bruce_tampa - Yes the gray wire going to the Rainbird should terminate at it’s transformer. Turn off the circuit breaker and disconnect the wires from the Rainbird and then connect them to the Rachio outdoor enclosure.

Regarding belts and suspenders - they both hold pants up, so if one breaks the other still keeps the pants from falling down around one’s knees. If the local forecasts are fairly accurate then you should be fine. If there is a difference in the climate where the Rachio is installed versus NWS stations/forecast then I would be tempted to wire in the rain sensor.

I might leave the rain sensor wiring there, but disconnected to see what the results are.


Sounds like my install a few weeks ago. I replaced a RainBird ESP-SMTe controller (VERY similar to yours) for 13 zones with a Rachio3/16zone controller. As others have mentioned, this turned out to be FAR easier than I expected. I do have some OCD characteristics, so I labeled every wire with the zone number, a “C” for common, and “M” for pump relay. Took all of about two minutes to connect everything up correctly. In my indoor installation, and unlike the RainBird device, there is no internal transformer for the Rachio3, just a long plug with a huge wall wart at the end. Again super easy to plug in.

As for the rain sensor, I have one that came with the RainBird device. At present I’ve left this unconnected to see how accurate the Rachio3 is without it. So far, pretty good. If I start to water in the rain, I’ll connect the rain sensor.

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This is great because I am also a bit OCD or something - thinking I need to bring out my label maker for this.
My install is outdoor so had to wire the electrical cable; I like how they have the transformer plug into the enclosure then either hard-wire or pigtail connection. Flexible.
I wish there was more clarity between website and forum with rain sensors and weather intelligence… seems if urban area with lots of PWS use one of those (PWS) - otherwise use WI… but since you don’t know how accurate someone else’s PWS is - I think I will end up buying my own and likely use the Rain Sensor (but then the reports aren’t accurate)…OCD

Just to put closure … install was successful. The rain sensor transmitter was faulty so although I wired it I did not enable.
Both the rain sensor and pump start relay needed (1) additional hole which I had to drill… missed opportunity for Rachio to have additional that can be punched out.