Irrigation Equipment - Irrigation Controllers, Timers or Clocks

Irrigation Controllers, Timers or Clocks. All three of these terms refer to the same piece of equipment, a device that controls the irrigation system and turns it on and off at a desireable time and operates the system for a preset period of time. The preferred term among professionals for this piece of equipment is controller.

There are two basic types of irrigation controllers, electromechanical and electronic. Both types do essentially the same thing, but each offers unique features and benefits that may be desireable depending upon the specific project.

First introduced in the 1940’s and 1950’s, electromechanical controllers are well-regarded as a dependable solution for irrigation systems. Driven by electric motors and gears these units offer exceptional reliability since they have very few sophisticated electronic components. Power outages have a limited effect on these controllers since the watering schedule is mechanically programmed into the unit. In other words, the controller is set by turning dials or flipping switches to select when watering will start, how long each zone will water and what days watering will occur. The watering program is not eliminated by power surges or outages, and backup batteries are unnecessary.

The down side of mechanical controllers is that they are very basic in their capabilities. Today’s landscapers and water purveyors recommend that you water grass areas on separate zones from shrubs or groundcovers because of the different water use requirements of these plants. In addition, it is frequently recommended that specific areas of your landscape be watered at different rates or frequencies due to exposure to sun, poor drainage, or soil conditions. The typical mechanical controller lacks the ability to provide independent scheduling or accomodate these complex watering requirements.

Electronic controllers, on the other hand, have the capabilities to meet the needs of today’s water conscious and sophisticated landscape designs. There is a wide selection of models with varying levels of complexity.

In recent years, irrigation equipment manufacturers have made significant improvements to make their electronic controllers simple to program while at the same time adding more features and programming flexibility. Controllers have taken on names that indicate their ease of operation, for example one manufacturer calls their unit the ESP Series, which stands for Extra Simple Programing. Another manufacturer calls their controller the SRC, for Simple and Reliable Controller.

Today’s modern controllers can water given areas of the garden with the precision required by the most water conscious designer. In addition they can be programmed to apply water in short bursts, preventing run-off in the most steeply sloped areas.

Only the imagination of the installing contractor or the end user limits the water saving capabilities of the typical electronic controller. Unfortunately, in many instances the programming capabilities are not utilized to their full potential. Often, users do not give careful consideration to the watering needs of the specific areas of their lawn or the programming changes that are necessary with the changing seasons. It is unfortunately common that many of the systems in operation today are applying water according to the original program set by the original installer, sometimes years earlier. As lawns mature and as trees grow in adjacent areas, there is a need to reprogram the controller to realize water savings, or make seasonal adjustments and apply water according to the needs of the plant material.

For more information on scheduling your irrigation system, visit the Technical Information section.

One of the best ways to permit your controller to automatically compensate for rainfall (and thereby prevent unnecessary watering) is to install a Rain Sensor.

Special Note: Almost all electronic controllers require a 9 volt battery to retain their watering program during power outages. Consider changing that battery along with your smoke detector batteries once a year.

Irrigation Equipment Sections
[Controllers, Timers, Clocks] [Heads] [Valves] [Drip Irrigation] [Sensors] [Backflow] [Chemigation]

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