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Adding a Rain Sensor

Discussion in 'Irrigation' started by TXCanuck, Aug 16, 2005.

  1. TXCanuck

    TXCanuck LawnSite Member
    from Texas
    Messages: 1

    I'm tired of trying to remember to switch off the controller every time it rains, or is forecast to rain. I want to add a rain sensor to my system.

    I have a system that uses an Irritrol Rain-Dial RD-900 controller. I have been poking around trying to figure out how to install this rain sensor into the system. I see on the circuit-board that where it reads "Sensor +/-", but there are no screw-down mounting points like there are for the zones.

    My first question is this - can I add a rain sensor to this controller?

    Can a rain sensor be added to any controller/system? If so, how?

    Assuming that I can add one - which sensor should I go for? Wired/wireless?

    Thanks in advance.
  2. Dirty Water

    Dirty Water LawnSite Fanatic
    Messages: 6,794

    You can add just about any rain sensor to any timer by wiring it Inbetween the timer and the valves on the common line.
  3. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Messages: 2,781

    The rain dial should have two "sensor" terminals that are bridged with a metal clip. I personally don't like rain sensors because they won't do what you think they will. A rain sensor will prevent you from watering AFTER it has rained at least X amount. It will then dry up and turn your system back on with around 36 hours. If you had enough rain to justify not watering, then I want your controller off for 3 or more days. That's what I preach and teach. That is agronomically sound advice. With said sensor installed, you are still going to water until that 1/2" (or what ever you set the guage for) is reached. If it is summer time and your in a climate with 80+degree weather, that roof mounted sensor is going to dry out and turn your system back on in less than 36 hours. You could have a 6" or rain weekend like we did here last weekend, and your system would be back on to run tomorrow morning. I don't think the cost justifies end results. As far as brand, they all work, and they all work about the same way. Hard wired sensors are cheaper, but take more labor to install. wireless sensors can be installed in less than 15 minutes, but cost 3 times as much. Around here, a sensor is going to run you about $125 profesionally installed, reguardless of type.
  4. jeffinsgf

    jeffinsgf LawnSite Senior Member
    Messages: 641

    I read Bryan's advise in another thread a few weeks ago and decided against a rain sensor. But now we are leaving for two weeks of vacation and I decided skipping a few days when it rains is better than not skipping at all.

    I installed a Hunter Rain-Clik this morning. I think it addresses some of Bryan's concerns rather nicely. It has a collection of absorbent disks in the head that prevent the system from returning to work until they dry out. If they dry out faster than the soil, you can shut down the vents a little until you have it calibrated -- or at least that is what Hunter says. I will be watching it when I get back to see just how long it keeps the system shut down after a good soaking rain.

    The installation manual says that you can install on any 24V controller. If your system does not have the terminal and bridge like Bryan mentioned, you can just put it in the common line, breaking it before the terminal block.

    Hunter gets a demerit for the installation manual and instructions. No where in either the Pro-C manual or the Rain-Clik manual does it explain that the rain sensor does not affect manual operation of Hunter controllers. I was pulling my hair out trying to figure out what was wrong with it this morning. The manual says to start a zone that you can see from the sensor and then hold down the manual test button of the rain sensor. I was sure that everything was hooked up right, but it did not shut off the sprinkler. I called Ewing, and they said I had a bad controller and to take it all apart and bring it in for a replacement. Nice service offer, but a lot of effort to tear the 11 zone system apart and put it back together. I decided to do a little more trouble shooting before I went there. I had my wife watch the controller while I pressed the test button, and it gave the correct indication (OFF - sensor). I became suspicious of whether the controller was designed to bypass the sensor for manual starts, so I programmed in a start time, let the system come on and then climbed the ladder and hit the test button. The system shut off immediately. Shot it with a hose and the same thing,

    I don't know if the Ewing counter guy assumed that I knew it would only work on program starts or not, but I know Rainbird does not work this way (had an ESP at my last house). He almost cost me a half day's work and Ewing the replacement of a perfectly good controller.
  5. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Messages: 2,781


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