Replacing Weathermatic SL1600 with Rachio 3

I have not purchased yet, but considering moving from SL1600 to R3, mostly for modern app control. A question about wiring and another about control:

  1. This is my present wiring, and it appears there are more wires here than on the Rachio unit, so I assume that means some consolidation of the power wiring?

  2. We have a seasonal technician that comes for Spring setup and Fall shutdown. Can I give control to this fellow?

Thank you!

Forgot the wiring photo:

@dn325ci - 1. Straight forward migration if you want to do it (notes below)

  1. Yes, you can have your technician have access to the unit via the app.

Wiring - looks like there are 8 zones, no master valve or pump start relay and a wireless rain sensor in the configuration.

Zones 1 - 8 go to the corresponding zone terminals on the Rachio.
COM - goes to one of the Rachio C terminals.
The thin red wires from the white jacketed (wireless rain sensor) cable go to the 24 VAC + and - terminals - doesn’t matter which one.
The white wire from the white jacketed cable will go to the 24 VAC - terminal also.
The brown wire from the white jacketed cable will go to the S1 (or S2) terminal and set that terminal to be a rain sensor.

Any questions, just post back and someone will probably respond.

Welcome to the community.

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I acknowledge what @DLane said. I add that I recommend making sure all zones are working right before disconnecting and labeling is always helpful, but not as necessary if you are able to bring over one at a time or no ambiguity in the colors. I also would recommend getting it working without the sensor first. In the matter of fact, depending on your area and where the weather stations are, you might find you do not need the sensor. It seems like most end up not using it. You can always hook it up if you want later.

Thanks @DLane. Very helpful, and I think I can wire it from your instructions.

Thanks @Thomas_Lerman and I’m quite happy to ditch the rain sensor as I don’t like the way it looks on my house anyway. I live in SW Ohio Cincy-Dayton area, we get a pretty solid amount of rain.

Follow up question: I spoke with our seasonal service tech who said he was more familiar with B-hyve and the Rain bird controllers. He didn’t sound like he was necessarily against it - just unfamiliar with Rachio. I don’t really know all he does during these Fall and Spring visits, but is he going to easily be able to figure it out from the app? I’m obviously no expert to teach him.

Thank you!

I might not suggest removing the rain sensor right yet. I would guess the forecasting would be good in your area, but just in case.

I would guess he should be able to figure out the app, but it really might depend on what he is doing. If it is something as “simple” as winterizing (turn off water, blow out or otherwise drain, and put in standby more) and de-winterizing (take out of standby, turn on water, and check & potentially fix zones), he should be able to figure it out (and by then you teach him some things if needed, but doubt it).

Thank you @Thomas_Lerman . I ordered the 12 zone version from Costco (was cheaper than 8 zone version) and I’m going to install it per @DLane wiring map over the weekend. I’ll report back. Cheers!


I installed the Rachio 3 today, and it could not have been more straightforward with the wiring advice that was given here. Very easy.

Zone setup and testing also very easy - Rachio has a well thought out setup routine.

The run times established by the automation were longer for some of my zones than the programming in SL1600 controller. I’m going to try the recommended settings to see how it goes.

Q: after the setup routine I manually went to Controller Settings - Accessories and added my existing wireless Irritrol rain sensor to Sensor Terminal 1. I have no idea how that will affect the programming I established during setup?

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Getting the zone times right is dependent on the zone Advanced Settings. Choosing the type of vegetation and sprinkler head will get you in the ballpark, but a catch cup test will give you the most reliable information regarding inches per hour. That’s probably the one setting you’d want to touch.

The rain sensor will act the same as it did with your old controller: interrupt watering schedules if the sensor swells to a certain degree based on the amount of precipitation that has already fallen. You can adjust that trigger amount on the sensor itself.

I suggest turning on the Rachio skip options; they’ll range depending on the type of schedule you set up (flex daily, flex monthly or fixed). I am near Austin TX and in a pretty significant drought, so I have to use Fixed right now but default back to Flex Daily when not under water restrictions. Side note: warm season grass really seems programmed for St. Augustine and not Bermuda, which can thrive on about half as much water. There are some really smart people in this community, so dive in and enjoy the app really doing all the hard work.

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