Rain sensor question

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HudsonDIY

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Greetings all,

I recently purchased a Blossom 7 irrigation controller for my home irrigation system. I'm not using all the fancy features such as the smart watering. I just wanted a controller I could sit my butt on the couch and program or turn on or off. They don't include connections for a rain sensor presumably because you are supposed to be using their smart watering. Quite frankly I don't trust them to accurately detect rain here in Florida. Other than that I love the controller. Yes I know there are better out there, it's hard to beat.

This brings me to my question. I assume the standard rain sensors are normally closed or normally open switches. Thinking normally closed, at least I hope so. With that in mind wouldn't it be possible to connect it in-line on the common ground connected to the valves in order to break the ground connection when it rains? I'm sure the controller is going to report an error but I can live with that.

Thanks in advance for your replies.
 

WorthFlorida

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Just need to get the standard rain sensor sold everywhere. You can get wireless setup if needed. All it does is open the 24v AC to the motor relay or as you suggest open the common side. The controller will still run its program, however some controllers do have a rain sensor terminal that shuts down the program.

The rain sensors are three wire so you can have a NC or NO set of contacts. It’s work by a stack of leather washers held together by a plastic pin. When the leather expands when wet it operates the switch buy pushing down on the pin.

Location is important so it is exposed the to weather but when sitting in the sun after the rain, the leather will usually dry out in a few hours when watering may not be needed for days after a long rain event. Most do have an adjustment to to slow down the evaporation rate.

This the most basic type sold under various brand names.
https://www.rainbird.com/products/rsd-series-rain-shut
 

HudsonDIY

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Thanks for the replies. Yes I have an existing sensor which was connected to terminals on the old controller (an older Rainbird) specifically for that use. I just wanted to be sure what I wanted to do would work before I went to the trouble of hooking it up and climbing up a ladder to dump a bucket of water on it. As WorthFlorida knows it drier than a popcorn fart here in Florida right now so its going to take some coaxing to test. Its currently connected to a gutter on the side of the house but its under a tree so that location may not be ideal. I'm honestly not sure if it even works but getting a new one is the simple part.

Thanks again,
 

WorthFlorida

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On the top of the rain sensor the pin sticks up slightly. You just need to push down on it and it will activate the switch. Before going up the ladder, turn on a zone, then push the pin down. It sometimes takes a fair amount of force to push it down. It only moves maybe a 1/16 of an inch.


Screen Shot 2019-09-25 at 1.57.48 PM.jpg
 

HudsonDIY

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On the top of the rain sensor the pin sticks up slightly. You just need to push down on it and it will activate the switch. Before going up the ladder, turn on a zone, then push the pin down. It sometimes takes a fair amount of force to push it down. It only moves maybe a 1/16 of an inch.

Thanks for the tip, will give that a try.
 
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