Can Rachio 3 replace my existing Hunter sprinkler system?

I have a Hunter sprinkler system that has two zones and 21 watering stations programmed in the set up. I am not able to figure out if Rachio 3 (any of 8/12/16 zone) is compatible? I am very much a novice in this space and so if any more info is required about my existing system, I will be happy to provide that. I am attaching two pictures to show my current wiring of the 21 stations. Appreciate your help in advance. Thx

@sk19 - The Rachio system can replace the Hunter, with the following caveat:

One will either need two Rachio systems (e.g. an 8 and a 16 zone) to cover all 21 zones or double up 5 zones on a 16 zone controller. I’d vote for two systems. Note that the two systems will run independently of each other, i.e. it won’t act as one large controller to prevent two zones from watering at the same time. Depending on how long the zones run (i.e. are they long running drip zones), the systems may be able to have different start times or restricted to specific days to prevent them from running at the same time.

Hi DLane,
I did fear that I may need to reuse 5 of the zones on the Rachio3-16 zone unit. Or as you suggest, having two Rachio3 systems is another option. I am the second house owner for my property and not fully convinced that we really need 21 zones in our yard in the first place. May be I should take a 2nd look at my current irrigation sprinkler system design and see if I can bring the zones down to 16 or under. It seems a bit clumsy (and expensive) to have two Rachio3’s to solve this 21 zone problem. I can also look at reusing five of the zones or take a look at Smart Hunter sprinkler solutions as well. Appreciate your advice. Thx

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Depending on how the system was plumbed together, you may have some zones that can run simultaneously. This is how I went from 18 to 16 to allow one controller. The other benefit is it significantly reduces the total run time which is probably long with 21 zones. You might try wiring up a couple zones to test the water pressure output. Generally running 2 from the same box won’t work, but running 2 from 2 different valve boxes can work pretty well.

I went from a 20 zone Hunter just like you to a 16 zone Rachio. I had a number of grass zones that could be paired up with no ill effects. @wafflesngravy recommendation to pipe them together would be the best route, but I was lazy, and have continued to be lazy and just wired my zones together. I don’t have a master valve, pump, or anything, so Rachio has no issue powering multiple valves at once. It doesn’t look like you have an MV or pump, so you could do similar…

If you can, describe the zones briefly. Example are there any that are drip systems? And if so how many? And do you have an idea of the length of each drip system?

How many sprinklers and what type of sprinklers on other zones?

These types of things will allow people here to give you suggestions to look into on how you might consolidate down to 16 zones.

Careful running two separate controllers… it gets tricky sharing a common ground wire. I like Rachio and have installed over 100 controllers for customers… but they are behind on systems with over 16 zones… You may want to check the Hunter Pro HC. They make one for 24 zones.

If nothing else just buy a cheap rain sensor.

You can combine zones if the following conditions are met:

  • their aggregated flow does not exceed the capacity if the main line
  • the pressure does not drop beyond the sprinkler’s requirements
  • the plants in the zones have similar watering needs (length and duration)

In general, drip lines need little pressure and can be combined easily. I am quite sure there are many low-flow zones in your system that can run together.

It comes down to looking at each zone, find out which sprinklers belong and how much water they consume.

If you can’t get down to 16, a Hunter controller with 24 zones might be a better choice. With modern smart controllers, it’s not easy to configure two controllers so they don’t conflict. The flexible schedules make scheduling complex since watering days for each zone change with the weather.