# Wiring a Master Valve, Pump, or Common Wire to Two Controllers
> Summary This article will help you with instructions on how to wire one master valve, pump, or common wire to two Rachio controllers. CAUTION Interc...
Source: https://support.rachio.com/en_us/wiring-a-master-valve-pump-or-common-wire-to-two-controllers-BkhiPIJFD
Last updated: 2026-04-13T23:26:28.278Z
# Summary
In this article, you will find instructions and video tutorials on how to wire one master valve, pump, or common wire to two Rachio controllers. These instructions are valid for all Rachio controllers (Generation 1, Generation 2, & Rachio 3. This is also a very helpful setup for users with more than 16 zones.
## Contents
1. [Shared Master/Pump Installation](#section-1)
2. [Shared Common Installation](#section-2)
3. [Video Tutorial](#section-3)
#### CAUTION
Interconnecting two controllers sharing the same common wire without the following provision is a violation of the National Electric Code. Failure to follow these recommendations could cause severe damage to the controllers and any adjacent equipment.
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**Parts List:**
* Isolator (one for each controller). [Order directly from Easy Irrigation Repair](https://easyirrigationrepair.com/product/isolator/) and save 15% with code **"RACHIO",** or [order on Amazon](https://www.amazon.com/ISOLATOR-Irrigation-Controller-Multi-controller-Interconnection/dp/B008RQ58R4) at retail price. Isolators will be required for both shared master valve/pump wiring and shared common wire installations.
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## Shared Master/Pump Installation
**1\. Unplug Controllers**
Power to each controller should be off prior to wiring.
**2\. Wire Isolator <-> Controller**
The black & white pair of wires on the Isolator connect to the controller
Connect the black wire to the Master Valve terminal.
Connect the white wire to one of the Common terminals.
**3.Wire Isolator <-> Isolator & Field Common**
The red & white pair of wires on the Isolator connect to the valve field wire.
Connect the red wire to the hot wire going to the pump/master valve.
Connect the white wire to the common wire for the pump/master valve.
**4\. Repeat**
Repeat steps 2 & 3 to install an Isolator on each additional controller.
**Completed Example**
The following image shows a working example, from a two-Rachio user:
_(click to enlarge)_ 
#### NOTE
We do not currently support split master options.
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### Testing:
**1.** Activate all controllers to ensure they are watering correctly.
**2.** If step 1 fails, attempt the following:
* Apply 24 VAC power to the black & white pair of wires; 24 VAC should be passed to the red & white pair of wires.
* Apply 24 VAC power to the red & white pair of wires; 24 VAC should not be passed to the black & white pair of wires.
#### Note
Controllers wired in this way _can operate simultaneously_.
Please be aware, however, running two zones at once will likely affect your overall water pressure. To avoid issues with proper coverage, it is recommended that zones with higher pressure requirements be placed in a schedule with offset watering windows.
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## Shared Common Installation
**1\. Unplug Controllers**
Power to each controller should be off prior to wiring.
**2\. Wire Isolator <-> Controller**
The black & white pair of wires on the Isolator connect to the controller.
Connect the black wire to the Master Valve terminal.
Connect the white wire to one of the Common terminals.
**3\. Wire Isolator <-> Isolator & Field Common**
The red & white pair of wires on the Isolator connect to the valve field wire.
Connect the red wire to the red wire coming from the other Isolator(s).
Connect the white wire to the common wire for the valves in the lawn.
**4\. Repeat**
Repeat steps 2 & 3 to install an Isolator on each additional controller.
* * *
### Testing:
1. Activate all controllers to ensure they are watering correctly.
2. If step 1 fails, attempt the following:
Apply 24 VAC power to the black & white pair of wires; 24 VAC should be passed to the red & white pair of wires.
Apply 24 VAC power to the red & white pair of wires; 24 VAC should not be passed to the black & white pair of wires.
#### Note
Controllers sharing valve commons need to be programmed so they do not operate simultaneously.
This requires offsetting the watering windows to ensure the controllers do not run at the same time. The first controller must complete its irrigation cycle before the second controller begins. If both controllers attempt to operate simultaneously, the valves for Controller A will run, but the valves for Controller B will not.
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## Video Tutorial
**This video tutorial is intended to assist irrigation professionals with the installation of Rachio Smart Sprinkler Controllers.**
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