Sprinkler Controller - Questions on replacing old Nelson controller


I’m replacing an old (20+ years) 8-zone Nelson SmartZone EZ controller with the new Wyze sprinkler controller.

Everything is straight forward, except for the rain sensor. It is connected to its own little section on our old controller, marked with a + (light pink wire) and a - (light green wire). I’m guessing I connect these two wires to the corresponding + and - terminals in the black section of the Wyze controller, but can anyone verify that for me?

Thanks for the help!

They have a page with support on various models of rain sensors and their wiring schematic. → https://wyzelabs.zendesk.com/hc/en-us/articles/360052569471

That being said it should be pretty straight forward. The “-” light green cable should go to the Wyze “-” connection and the “+” light pink cable should go to either S1 or S2. Make sure in the app you then update the terminal connections and tell the controller what you have connected on those terminals.

For me I am using a Toro rain sensor. The one weird thing is that it seemed my wiring of -/+ was backwards. To me that doesn’t really make sense but I kept getting rain sensor skips even though it had not rained outside. So I switched them and all appears to be right in the world.

I checked that page before I posted here. They don’t show Nelson controllers, and they don’t show any rain sensors that just connect to the +/- terminals. The only two wire rain sensors they show use the middle two terminals in the grey section - the - and S1 terminals.

I assume it can’t hurt anything connecting a rain sensor to the wrong terminals; I’d just like to know which ones are correct if I can.

They won’t because the +/- are for power in only. The rain sensors just need the common (-) and it’s terminal (S1 or S2).

Rain sensors most often seem to be simple open/closed circuits hence why for most connectivity isn’t an issue. On yours I would follow the previous schema and wire - to the grey - and wire + to the S1/2

Yes, ours is simply a little device that sits on top of our gutters. It has a sponge in it which swells when it gets wet. That opens or closes the circuit; I’m not sure which. The - / S1 configuration makes sense. I’ll give it a shot and report back. Although I may have to actually wait for our next rain unless I could somehow activate it with the hose.

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