Large Project


I have a hunter icc and have about 36 stations. I saw that I may have to get isolators additional to the rachio. Can someone confirm and if so, it would be 3 rachios, 2 16 zone and an 8 zone, how would this work? Can’t I use some kind of relay system if this is necessary? This is also an outdoor system so it would all need to be in the outdoor enclosures.

Here is the system in question.


Good news is that your setup does not feature a master valve or any kind of sensor that I can see, thus you will not have to deal with an isolator or any sort of relay setup.

I see that you have at least four common lines. It is possible that you will be able to segregate your setup into four separate groups, but you will end up bridging at least one group between two different Rachios. This should not be a problem since voltage potential needs two points of contact for current to flow, and having only commons interconnected between the Rachios will not cause an issue.

If you are considering Gen 3 controllers with their flow meter capabilities. @jsore has outlined (link) a way to make this work with three additional master valves, since each of the new master valves would be connected to an individual Rachio, there should not be a need for isolators.

Have you considered how you wish to setup your schedule? Are there any watering restrictions where you live?



I figured I would schedule the 2 large controllers to every other day and the 8 controller off hours. There aren’t watering restrictions but water is expensive here. Can you clarify the bridging between two rachios and if I need to do something different since they will be in outdoor enclosures?

Thank you for the help!



By bridging, I was referring to connecting the common wire together. Connection would take a form of a Y whereas there is a cable running from a common terminal of 2 individual controllers.

Something like this:


Connection can be done outside of the enclosure, if needed.

Rachio supports setting schedule to start or complete relative to a certain time. So if you set one controller to start on that time and the other to complete by the same time, they would work well gother. The third controller would need to be offset by a couple of hours to avoid multiple zones running at the same time.