How do I install a rain sensor? (Generation 1)

Last Update:Oct 19 2023 8:15pm • Est. Read Time:Est. Read Time: 2 MIN

Summary

In most installations, a rain sensor acts as a switch; as moisture absorbing disks expand, they activate a switch that interrupts the circuit from the controller to the solenoid valves. Once the rain sensor has dried out, the switch deactivates to allow for normal operation.

The Rachio  1st Generation  Smart Sprinkler Controller is compatible with any wired or wireless normally closed  (NC) rain sensor, which activates after rainfall (when the moisture-absorbing disks expand). Want to learn how the rain sensor is installed in your Generation 1? This article is for you.

NOTE

The Rachio 3 and the 2nd Generation are also compatible with any wired or wireless normally closed (NC) rain sensor. For  Gen 2 wiring instructions, please refer to this support article. For Rachio 3, go here.

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Installation Guide

Prior to installing the Rain Sensor, take a few moments to read through these instructions in their entirety. The rain sensor must connect ONLY to the following terminals on your Rachio Gen 1 device:

  • rain sensor (  R1,  R2  ) terminals -  for basic wired sensors 
  • common (  C  ) terminal -  for wireless (powered) sensors

Do NOT connect the rain sensor to any of the zones.

 Installation methods must comply with all applicable national and local electrical codes. If you are unsure about proper wiring practices, have a qualified contractor perform the installation for you.

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How To Connect Rain Sensor Wiring

1) Disconnect the power to the controller.

2) Route  the Rain Sensor connection wire into the controller through the access hole in the base or bottom of the wall mount

3) Locate your controller's sensor terminals (yellow) and attach the Rain Sensor control wires directly to these terminals (in either order) -- see diagrams.

4) Enable  the rain sensor in the Rachio App > Select the Settings Wheel to the top right > Controller Settings 

5) Reconnect  power to the Rachio

 NOTE:  Avoid routing the wire over any sharp edges where damage to the wire insulation may occur. For best results, hide the wire as much as possible by tucking it under shingles and/or moldings. Seal any holes made by passing the wire through structure walls.


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Rain Sensor Wiring Diagrams


a) Wired Rain Sensor (basic non-powered)

To connect a  wired rain sensor  to your Rachio 1st Generation controller, please see the wiring diagram below:

b) Wireless Rain Sensor (powered transponder)

To connect a  wireless rain sensor to your Rachio 1st Generation controller, you can find model-specific diagrams in the links, below:

 Compatible Rain Sensors (Click name for Specs & Instructions) 

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Enable in App

To activate the rain sensor in the Rachio app, please follow the steps below:

1) From the Events screen, select the "Settings Wheel" at the top right of the screen and then "Controller Settings." 

2) Go into "Accessories", then select "Sensor (S1 Terminal)". You may only add a rain sensor to this terminal if there is no one currently installed. If there is a sensor installed, select "Sensor (S2 Terminal)", the option below S1. 

3) Enable the sensor by toggling it on.


4) Select the type of sensor you're adding (in this case, "Rain").

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Check if it Works

To test the Rain Sensor operation, please review:  How to test a rain sensor

NOTE

For more detail, see article:  Rain Sensors FAQ