How Do Irrigation Controllers and Sensors Work?
Understanding Irrigation Controllers
Irrigation controllers are not installed in many places, meaning residents have to manually turn on each station to water their lawns. It’s time-consuming and cumbersome, and it wastes water. But if you use a controller, tell it when and how long to water, the irrigation system will automatically water, very convenient.
What Is an Irrigation Controller?
An irrigation controller is the clock that runs a sprinkler system. You program it to water at particular times of the day and for particular lengths of time, so you don’t have to do it by hand. A good controller, programmed well, can make the difference between a landscape that is efficiently watered and one that is not.
Really large sprinkler systems covering a lot of area may have more than one. Each controller will have several stations (timers) that water different parts of the landscape. Older controllers and their stations are programmed manually, with the landscaper guessing how much water each section will need.
Irrigation Controllers With Sensors
Newer ones connect with special sensors to take weather and other factors into account, modifying programmed schedules to water only when plants are thirsting. The newest ones connect via the Cloud, accessing regional weather conditions, and allowing a homeowner to change the program from a distance.
Controllers can have a strong effect on the monthly water bill. Property managers who inadvertently water their landscapes too much or at inappropriate times of the day nearly always end up with high water bills.
What Are “Smart” Controllers?
There are several different kinds of Weather-Based Irrigation Controllers (WBIC) or Smart Controllers. All of them work by using information about the site, input by the landscaper, combined with information transmitted from local sensors or satellite weather stations to modify the watering schedule.
Weather-Based Irrigation Controllers use information like weather readings, moisture in the air, moisture in the soil, solar radiation, plant types, soil types, slopes, and water pressure. These factors affect the amount of water retained by plants in a landscape, thereby altering the amount of water the controller must allow through a sprinkler system to keep the landscape healthy.
How Controllers, Stations, and Valves Fit Together
Controllers can have anywhere from four to 200 stations hooked up to valves that regulate sets of sprinklers watering a particular location––like rotors that water lawns or bubblers that water bushes. The stations send electrical impulses to their respective valves to open or shut them, letting water through to the sprinklers (or not).
Because this works electronically, the controller has to be physically located near enough to the valves to allow for a wired hookup. The location of the valves therefore determines how many controllers you will need and where you will place them (or where you’ll find them, if they were already installed when you got there).
For example, if all the irrigation valves on a one-acre plot are located on one side of the house, that’s where the controller will be. This landscape will likely have only one controller with, say, eight stations. One station might be programmed to water trees and bushes, another to water grass in front, a third for a drought tolerant section, another for medians or parkway, one for a shady section, and another for grass in back, with each section having its own schedule.
On the other hand, a six-acre site with many different types of plantings spread throughout could conceivably have eight or more controllers with an average of 64 stations each. That’s the general gist of the controller/station/valve setup.
One of these valves sprang a leak and needed to be replaced. You can see the wiring that hooks each valve to its station timer on the controller (located out of view).