Rain sensor tied to common?


Recently changed the rain bird that came with my house to a Rachio. Worked fine for awhile, but after a recent rain storm (and freeze), it seems I can’t turn on the zones. It claims to be running, but no water is coming out.

I took photos of the old controller. There is a rain sensor along our fence line the runs down to a PVC pipe in the ground. However on the old controller, there was no sensor cable. Instead it was simply a short cable that was looped into a U and one end connected to sensor 1 and other end to sensor 2.

Does this mean that the rain sensor is somehow tied into the common wire? Will this by default trigger my controller from letting me run zones/schedules when it rains (even though I have rain sensor setting off in the app)?

If that’s the case, any way to separate the two so that they’re not tied into one another? Or does none of this explain why my rachio isn’t allowing me to run zones (although the app believes it is running the zones as requested)?

The short wire using means no sensor is connected to it, but maybe yours just ties into the common wire. Do you know the brand and model of the sensor?

@Pers785 - sounds like the old way of wiring the rain sensor that is far from the controller. The rain sensor is normally closed, when the rain or temperature trigger the sensor it opens the connection. When it is connected in-line on the common wire, this prevents any zone from running. Rachio (or any other controller) will continue on merrily thinking it is watering.

There are three options.

  1. Leave it like it is - least desirable.

  2. Cut out the rain sensor and connect the common wire together and let Rachio’s weather intelligence run the rain and freeze skips. Easiest and cheapest.

  3. Get a wireless rain sensor and connect it to the Rachio after removing the old rain sensor and connecting the common wire together. Belt and suspenders approach as this will catch the unforecasted local rain shower and doesn’t require running wires from the rain sensor back to the Rachio.

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Thanks for the reply!

I do not know the exact model of the rain sensor but can check when I get home - I believe it’s a rain bird

Any links that might help walk through how to cut out the rain sensor? I see the cable that runs from rain sensor on top of the fence to the PVC pipe under ground, which is the only section I can access the rain sensor cable from what I can tell.


I would presume that the rain sensor has two wires coming off of it. Following where they go may be a chore. The first place I might look is in the sprinkler boxes that contain the valves. Worst case, you could cut the wires going to the rain sensor and tie them together (presuming it is just two wires). This might make it difficult to connect the rain sensor in the future if you wish (I probably would not).