Programming Irrigation Controllers

programming an irrigation controller

What's the number one reason for customer complaints and callbacks? If you're like most irrigation contractors, an improperly programmed controller is the typical answer.

Today's irrigation controllers offer a variety of features and program options. As much as these modern marvels help improve the flexibility of an irrigation system, they do increase its complexity and, sometimes, the frustration you'll experience servicing it.

The following tips will help give you a basic understanding of how a controller works, how to program it and what some of the more complex features might be.

Basic Programming Techniques

The controller energizes the remote control valves that operate the sprinklers according to the program you set. Basically, it is an automatic timer which runs a pre-set program that regulates when and how long a sprinkler should run. The program dictates which days of the week the sprinklers will run, the time of day and total run time per zone (or station).

Many controllers can contain more than one program., and a few models contain independent programs. Each station may have its own program, which will allow you to enter a different start time, run times and different days of the week than the main program.

When a controller is initially set up, you must first program the current time and the day of the week. All irrigation controllers need at least three elements to produce a working program: start time, days of the week to start, and run times for each station.

Follow three steps to establish a basic irrigation program:

1) Set the start time. The start time is the time at which you want the controller to begin watering. Once the start time is set, controllers begin the watering cycle with the first station; the other stations in the program follow in sequence.

It's important to note that start times apply to the entire program, not individual stations. As such, depending on the controller, you may want to assign several or multiple start times per station, per day. For example, if you have a newly established lawn, you may wish to water several times a day to keep the seed or sod moist.

2) Set up the days to run the program. Watering days are the specific days of the week on which watering occurs (e.g. every Monday, Wednesday, Friday; or every third day). A watering schedule is the list of days on which a program runs. Different controllers allow different schedule options such as a 365-day calendar, a weekly calendar every other day, every third day, odd/even days, etc. Again, the watering days apply to the entire program, not the individual stations.

3) Set the station run times. Station run time is the amount of time each station will operate. The length of a station's watering period is called the run time. . Most controller run times can be set in one-minute increments up to several hours. For special situations, some controllers can be set in seconds.

Station run times are set individually for each station and do not apply to the entire program. So if a station does not have any time set to run, that station will be skipped and the next station, in sequence with a runtime will operate.

Electromechanical Controllers

The simplest controllers-electromechanical "clocks"-use gears, dials, and pins to control the irrigation program. These types of controllers usually have three separate dials to controls a separate functions: start time, day of the week to water, and station run times.

To program an electromechanical controller, push the pins in for "on" or leave them up for "off." As the dials turn, the pins that have been pushed in press against the contacts, completing an electrical circuit.

Electromechanical controllers are reliable and easy to use. However, they offer fewer features than electronic or hybrid controllers. They are ideal for customers who like to keep things simple.

Electronic and Hybrid Controllers

Solid-state or electronic controllers are essentially small computers. They offer more features than the electromechanical controllers. As such, they are more complex.

Programming a solid-state controller usually requires entering commands through a keypad. The results of the commands are visible in a display window; similar to a hand-held calculator.

Hybrid controllers combine the ease of use of the electromechanical controllers with the versatility of the solid-state controllers. Hybrid controllers have sophisticated electronic circuitry combined with an easy-to-use panel that features dials and switches. A display window guides you through programming and displays information about the watering cycle.

Solid-state and hybrid controllers offer multiple programs. This feature is useful for meeting the watering needs of different areas of the landscape. For example, a heavily shaded area requires less frequent watering than a sunny area. By using a different program for the shady area, you can effectively water it without under-watering the sunny area. Each program requires the same three basic elements of an irrigation program.

Master Valve Control

An additional feature to consider when programming a controller is the "master valve/pump start." Controllers often have a connection for a master valve or pump start relay. In some cases, this connection can be associated with each station. This means that every time the station operates, the pump start relay or master valve will also operate.

A master valve start is helpful if a station needs extra water pressure. It allows you to operate a booster pump when that station is operating. Or, you may have a master valve that controls the flow of water to the irrigation system. In this case, you will want to activate the master valve automatically whenever the program operates.

Note: Make sure the master valve/pump start must be wired properly to perform this function. See your controller's manual for instructions.

Shut-down Programs

Most controllers also have a switch to shut down all the irrigation programs. This is especially useful for turning off a controller when it is raining or when it has been cloudy and the soil does not require additional watering.

On more sophisticated controllers, a "rain delay" feature is available. Rain delay allows you to turn off the irrigation system for a specific number of days without having to remember to turn it back on. For example, if the weather forecast calls for three days of rain, you could stop irrigating for four or five days. This gives the soil time to dry out after the rainfall.

Many irrigation systems can have a rain sensor installed that automatically prevents watering when it detects moisture. The sensor override, or bypass switch, on a controller lets you turn off the sensor so you can resume irrigation. This is especially useful when troubleshooting a system. In most cases, you simply move the sensor override switch to off. You can then run the station and reactivate the sensor when you are finished.

Water Budgeting

Most solid-state and hybrid controllers feature a water budget function. The water budget function allows you to change the normal station run times without resetting each individual station.

With water budgeting, one hundred percent is the normally programmed station run time. You can adjust the run time up or down (zero to 300 percent) when you want more or less watering time. This adjustment is done on a percentage basis and is very effective for adjusting for seasonal weather changes.

If a station that is set to run for ten minutes. If you adjust the water budget to 50 percent, it will then run for only five minutes. If you adjust the water budget to 150 percent the station will run for 15 minutes.

Some controllers apply the water budget to all programs and stations on the controller. Other controllers offer added flexibility of letting you set a different water budget for each program. With these controllers, you can adjust the water budget to zero percent to temporarily turn off a program while you let the other programs operate normally.

The old adage is true: knowledge is power. Understanding the three basic elements of irrigation controller programming -- start time, days of the week to start, and run times for each station -- will ultimately cut down on your frustration, and hopefully reduce customer complaints and callbacks.

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