September
2006
Controllers for Automatic Sprinklers0
Controllers are an integral part of an automatic sprinkler system, and I wanted to make a post about controllers in general.
Many people call it a timer, and it is used to control when your sprinklers come on and turn off, and how long to run them. Without going into great detail about how automatic sprinkler systems are designed, your system will usually be divided up into different zones. Each zone controls a variable number of sprinkler heads, and each zone has a valve. The controller, or timer controls these valves. By default they are off, but when a small electric current is sent from the controller, it opens the valve and lets water through and out to the heads. Contrary to may beliefs, the pressure of the water is what makes the heads go up, the automatic timer only controls the valves that let the water through.
There are many different brands and styles of controllers / timers, and many accessories for them, from sensors for rain and wind to remote controls. But most automatic sprinkler timers have the same basic functions. The typical controller will have run times, start times and programs.
Run times are simply setting how long each zone will run. Depending on the type of heads and ground that is being covered the run times may vary per zone.
Start times are simply when you would like the zones to start running. You can usually set the start time to happen 3-4 times a day, and it will go through all the run times for each zone once for each start time.
Programs add another dimension to your start times. You can make a program that runs all your zones twice a day. You can then make a seperate program that runs only one zone once a day. An application for this would be if you want to water your lawn twice a day but only run your drip system once a day.
Controllers go on with many more features, such as percentages, response to sensors and many combinations of watering programs and start times, but this is basically how it works. Most controllers will also have a back up battery in case the power goes out. This usually won’t run the sprinklers when there is no power to the timer, but it will keep your settings so you don’t have to enter them again, and that is a good thing.
Pictured here are Virtualrain controllers, but there are many different brands each with their own pros and cons. Finding the right one for you involves first making sure that it covers the number of zones you have, and then it’s just desired features from there.