Rain sensor wiring issue

Not sure what or anything I need to do here. My current system has a rain sensor that keeps the system from running when it gets wet. However, there do not appear to be any wires coming back to the controller. I believe it functions by opening the common wire that feeds to all nine solenoid valves. How will the Rachio controller react to this? Will it cause problems?

Can you post a picture of the wiring on your current system?

Don’t have access to a picture right now but I can describe it. There are only 10 wires coming to my controller. Nine of them are for zones 1 through 9 and the 10th is the common wire. There is no wire coming to the controller from the rain sensor, but it does in fact work. If I push down on it anything that is running stops (simulating it being wet). The assumption I am making is that all the common wires on the nine valves are tied into one and that passes through the sensor, effectively opening the common line when the sensor detects rain.

Hmmm, wonder if it is somehow wired into the common wire to stop any continuity in the system…can’t say that is normal, but that’s the only way I see it working without being tied to the controller.

If this is the case, this won’t work well with Rachio, as it will think that it is still watering. Depending on your schedule (flex daily vs fixed) it may cause issues with the programing and underwatering.

Sounds like I should probably just jump it out and then move it and wire it directly to the Rachio unit. Would I just connect it between the S1 and C connections in the panel?

@gaustin is the expert on sensor wiring…but I’m pretty most sensors need a 24vac leg too…

I assume that is what the S1 and and S2 are for. If I put a volt meter across S1 and C I read 24VAC.

Depending on the brand of rain sensor you have you should have at minimum two wires. One typically goes to S1 and one goes to 24VAC. What kind of system did you replace?

It was an 15+ year old Rainbird mechanical controller.

When you get a chance post a pic of the rain sensor. I would be shocked if it was even working, they don’t tend to work past a year in my environment.

Yes, your assumption is correct. You can connect the 2 wires together coming from the rain sensor if you can’t find where the sensor wires are connected (probably near your valves) and bypass your sensor so you can take advantage of rachio’s connection to a nearby dependable PWS.

Oh the sensor itself is fairly new, less than a year old.