Irrigation System Components- Controllers

The Key to Good Irrigation
Of all the many parts that make up an irrigation system, the controller is arguably the most important piece. The controller is the device that operates the whole system and regulates when, how often, and for how long the system runs. Some also have more advanced features such as sensors to detect rain or freezing temperatures, sensors to detect soil moisture, remote control, and settings to allow alternate watering frequencies for various types of plants.

There are two types of controllers. The hydraulic type is an older design. In this type of controller, the valves are connected to the controller via tubes. These tubes are usually made of plastic and are about ¼ inch in diameter. The water is released when the controller opens the tubes, which in turn open the valves. The newer systems, however, most often use the electric controller. In these systems, water release is more efficient. Instead of tubing, the controller connects to an electrical circuit. This circuit then operates a series of solenoids which are connected to each valve. This allows for better management of how the water is released.

There are many different brands and types available. Most vary with the number of valves that can be operated per controller. Some only support 4 valves each while others support as many as 40 valves on a single controller. Of course price is relative to the features and valve support of each unit. The more advanced units are actually not that new. Many models have been around for years but the cost was prohibitively expensive for the average consumer. Now, these units have become more affordable and have opened the door for more DIY installers to get the system they want at a price they can afford.

Now let’s look at a few units and prices to give you an idea of what to expect. First we have the Rain Bird ESP4M. This unit is an outdoor controller rated for 120V, and it can support up to 4 valves. These are relatively inexpensive, costing between $85 and $108 each. Next we move up to the 12 valve units. We’ll look at two of them. The Orbit Watermaster 91922 is a twelve station controller that features a multilingual LCD display, a remote control which is effective within a 300 foot range, and a wireless rain sensor. It’s a great buy, and you can find it for a little as $136.99.

Rain Bird also has a 12 valve unit, but it’s a bit more pricey. The Rain Bird ESP12MC is a commercial grade controller. This unit features four different programs, a calendar that is updated in real-time and also features Rain Bird’s proprietary water management software called Cycle+Soak. This unit costs between $450 and $497.

There are even economy controllers for those with tighter budgets or smaller yards that don’t require larger units. The ESPSM3 also from Rain Bird supports 3 valves per unit and is very affordable, costing between $24 and $34.