*The following is intended as a guide only. I make every effort to provide accurate info. Please make yourself familiar with your controllers manual prior to doing this. Most are available on the net for download. Please also be aware you do this at your own risk. homeone.com.au and I accept no liability for damage resulting from this "how to"
Well I do these often and every irrigation controller can and should have one attached.
A Rain Sensor, or rain switch they are known as, are now a necessary bit of equipment that shuts off your automatic irrigation when it rains or a frost occurs. (although ideally you'd want the retic to come on when there is a frost because the water will be warmer and prevent any damage occuring but it is debatable )
I am sick to death of seeing old mate and his gang of muppets with the retic on when it is chucking it down with rain. grrr.
Rain sensors are a great way to avoid wasting water.
They work by interrupting the earth or common circuit and stopping the retic from being able to work. like pulling the plug on it kind of
They start at around $40 for something half decent by say Toro or Hunter. Then the wireless ones start at about $80-90 and go up to around $200 for ones with more features.
The best ones in my opinion to choose are the Irritrol wireless rain switch and the Toro wireless rain sensor. The Irritrol is Toros budget brand and the Irritroll sensor is a basic version of the top of the wazza Toro wireless jobbie. The Irritrol wireless rain sensor/switch will retail for around $80-$90 and is one of the most common ones installed.
I picked up the Top of the wazza Toro rain sensor for a great price so have chosen it as the basis of this "how to". This really isn't hard to do yourself and I would only suggest paying someone to do it if you are very scared of drills.
http://i308.photobucket.com/albums/kk321/FuManchu5ltr/installing%20a%20rain%20sensor/1theunit.jpg
I might add too that the brand of sensor you choose does not have to match the brand of controller you have. (I will do a how to on controllers as well in the near future )
First of all is what you need.
*Some suitable wall plugs.
*A trusty drill
*A number 2 point phillips screw driver.
*A finer number 1 point phillips screw driver
*The sensor unit
*Wire stripper (optional)
*Soldering iron (optional)
*Hammer
*Drill bits (small for wall plugs and larger for possible drilling in controller)
*Flat head screw driver or similar for cutting off excess wall plug.
*stainless steel screws for number 2 point phillips head screw driver.
some of the said equipment...
http://i308.photobucket.com/albums/kk321/FuManchu5ltr/installing%20a%20rain%20sensor/3equipment.jpg
I start by removing the cover for the wires. These are all 24 volt so no real danger involved. disconnect the mains power or unplug the unit from the wall if not hard wired. (I have not done this as you will note but it makes me feel better to say to do it for your own saftey if that is a concern ) The mains electricity ****** behind the little cover in the bottom left of the controller featured. (A Hunter EC which is an excellent controller, now superseeded by the XC) The coloured wires are for each valve in the sytem and a few spares for extras.
http://i308.photobucket.com/albums/kk321/FuManchu5ltr/installing%20a%20rain%20sensor/2controllerbeforefitting.jpg
I start off by working out how to mark were the first screw goes. The antenna is at the same level as the screw hole so I can get it pretty close to the same level as the controller. Also the receiver has a door that flips down so make sure where you mount it won't hamper it opening, or be covered by the retic controller door when open. I have selected the right side of the controller.
http://i308.photobucket.com/albums/kk321/FuManchu5ltr/installing%20a%20rain%20sensor/4sensorrecievertopmount.jpg
Then once I mark the hole I drill it
http://i308.photobucket.com/albums/kk321/FuManchu5ltr/installing%20a%20rain%20sensor/5drillingholeaftermarking.jpg
Then I hammer in a wall plug and cut off the excess with a flat blade screw driver (or use any other suitable tool)
http://i308.photobucket.com/albums/kk321/FuManchu5ltr/installing%20a%20rain%20sensor/6cuttingoffexcesswallplug.jpg
Then put in the stainless steel screw (some should be provided, I used my own)
http://i308.photobucket.com/albums/kk321/FuManchu5ltr/installing%20a%20rain%20sensor/7installingthestainlesssteelscrew.jpg
The receiver hangs like a picture and I can now mark the location of the bottom screw with my pencil. (add that to your list of things you need )
http://i308.photobucket.com/albums/kk321/FuManchu5ltr/installing%20a%20rain%20sensor/8markinglowermount.jpg
Remove the receiver unit and drill the bottom hole you just marked. Then put in the wall plug as previous. all done...
http://i308.photobucket.com/albums/kk321/FuManchu5ltr/installing%20a%20rain%20sensor/9lowerwallpluginstalled.jpg
Next I choose how the cable will run into the controller. There is a hole in the base of it but I want this to look tidy so I drilled a hole through the side of the controller box where there was no risk of damaging anything. In other words there was lots of space behind there. (those wires are pulled away from the drill bit, no chance of drilling into them but be carefull if you choose to do similar)
http://i308.photobucket.com/albums/kk321/FuManchu5ltr/installing%20a%20rain%20sensor/10drillingsideofcontrollerbox.jpg
Here you can see the hole for the grey cable in the side and the controller box.
http://i308.photobucket.com/albums/kk321/FuManchu5ltr/installing%20a%20rain%20sensor/11holeonsideofcontroller.jpg
and now secure the bottom stainless steel screw to the receiver so it is all well and truly screwed to the wall and won't go anywhere with the hand of nature.
http://i308.photobucket.com/albums/kk321/FuManchu5ltr/installing%20a%20rain%20sensor/12fittinglowerscrewofreceiver.jpg
Next i twist all the wires at the end together and feed the grey cable through the hole I drilled.
http://i308.photobucket.com/albums/kk321/FuManchu5ltr/installing%20a%20rain%20sensor/13pullingcablethrough.jpg
OK now the next bit is you need to work out what type of controller you have. It will be one of three types no matter what brand.
The first is a controller with no provision for a sensor.
It will look some thing like this diagram.
http://i308.photobucket.com/albums/kk321/FuManchu5ltr/installing%20a%20rain%20sensor/15wiringdiagramnosensorinput.jpg
The common wire is supposed to be the black wire (but I have seen some ******* wiring before ) It will look something like this...
http://i308.photobucket.com/albums/kk321/FuManchu5ltr/installing%20a%20rain%20sensor/15wiringdiagramnosensorinput.jpg
The second option is a controller with provision for a sensor but it doesn't have a switch to switch a sensor on and off. This is called a closed circuit controller. These should have a bridge or jumper between the two sensor screws. This is done so the earth or common wire current is carried through from the first sensor screw(marked "sen" usually), to the second sensor screw (also marked "sen" usually) and onto the common wire screw (marked "c" or "com" with a black wire attached usually) allowing the system to operate without a sensor. It will look something like this...
http://i308.photobucket.com/albums/kk321/FuManchu5ltr/installing%20a%20rain%20sensor/16wiringdiagramsensorinputnoswitch.jpg
The third type is an open circuit controller which has a provision for a sensor and has a switch that can be operated manually allowing the sensor to be on or off. Usually located on the main part of the controller but sometimes behind the wiring cover (like on some Irritroll rain dial controllers) It will look something like this...
http://i308.photobucket.com/albums/kk321/FuManchu5ltr/installing%20a%20rain%20sensor/14wiringdiagramsensorwithswitch.jpg