CONTROLLERS

Irrigation controllers or irrigation clocks are sometimes referred to as the brains of the system.  There are many types of irrigation controllers. Some are analog or mechanical but the vast majority is electronic.  While the analog controllers have been the work horse since the 1960’s, the electronic controller has taken its place due to lower costs to build, compactness and flexibility.  There are many types of electronic controllers available but the ones dealt with here are the residential and light commercial ones.  Of these, the ones you will probably see will be either indoor mount or outdoor mount controllers.  Indoor controllers are designed to be used indoors and are not enclosed in a weather proof cabinet.  Indoor controllers attach to electrical outlets via a plug in transformer.  This transformer steps down your house hold voltage from 120VAC to 24VAC.  Outdoor irrigation controllers are housed in a weather proof cabinet and rated for outdoor use. Outdoor controllers have the transformer located inside the cabinet.  To hook up the controller, you must bring 120VAC into the cabinet and wire directly to the transformer.  Once the electricity leaves the transformer, it has been stepped down from high voltage (120VAC) to low voltage (24VAC).  The irrigation controller and the electronic solenoid valves are powered by the lower 24 VAC voltage.

 

The first step of troubleshooting an irrigation controller is to verify proper voltage before and after the transformer with a voltmeter.  On indoor controllers, this mean verifying you have 120VAC at the outlet and then testing for 24VAC where the cord from the plug in transformer connects to the irrigation controller.  On outdoor controllers, you need to check for 120 VAC where the incoming power attaches to the transformer and then check for 24VAC coming out of the transformer.

 

If you have 120VAC being supplied to the transformer, but do not have a 24 VAC output, replace the transformer with correct model replacement part.  It should be noted that often power surges can short out transformers.  Before replacing the transformer, check to see if there is any indication of hot spots on the circuitry of the controller.   By removing the face cover you should be able to identify any areas that may have been blackened by a surge.  If circuitry is damaged then replace the controller and transformer.

 

If the transformer checks out ok and there is still no power being supplied to the controller, check the fuse (if applicable) on controller.  Some irrigation controllers are equipped with fast blow fuses.  Remove the fuse and check the thin filament.  Always replace blown fuses with same amperage fuse.  Blown fuses are an indication of power surges that could also short electric valve solenoids in the field.  Refer back to the valve troubleshooting section to learn how to identify shorted valve solenoids. 

Today’s electrical controllers rely on circuitry and microprocessors to send power to the electrical solenoid valves.  If your digital irrigation controller begins to lockup or have errors in the programs, you may need to reset the microprocessor.  To do this, remove all power from the controller.  Disconnect the power supply and remove any backup batteries.  Wait 5-15 minutes for the controller to power down and then replace backup batteries and restore power.  Reprogram and then test controller.

 

 Programming the controller

To get the most out of an irrigation system the irrigation controller must be programmed properly.  If you take just a moment to access what you will be watering the process will not be so daunting. Most of the controllers on the market these days come equipped with the items listed in the terminology section below.  The exception to this is what we call “smart controllers”.  Those units have the ability to be autonomous after installing the base information.

 

Most of us have landscaping which is functional and pleasing but not intricate in design or maintenance.  Therefore keep the programming as simple as possible.  Most of us will not need to use all the programs and start times available on the controllers.  The only times these extra’s may come into play is in the initial establishment of the landscape.

 

The basic program consists of inputing the date, present time of day, and the year.  After that select program “A”  and input the days of watering needed, the zone run times and the start time(s).  The irrigation frequency and run times is dependent on the climate, soils and plant materials.

 

Terminology:

Programs-- Most controllers come with at least 2 and up to 4 programs.  Programs allow you to apply different watering schedules to various types of plant material that have non-similar watering requirements.  For example, annual flowers planted in raised beds may need to be watered everyday whereas grassed areas may only need to be watered 3 days a week.  In this scenario annual flowers may be on program A and lawn areas on program B.  It is important to note that whenever information is entered into the controller under any of the various programs, each program will run concurrently regardless of the program positioning switch or screen display.

 

Cycles-- The cycle section of the controller refers to the daily interval that the program will run.  Most controllers give you 4 options on how you can run the daily intervals.

Odd- This setting runs the program every other day on the odd             numbered calendar days.    

Even- This setting runs the program every other day on the odd numbered calendar days.

Custom- Lets you choose exactly which days of the week the program   will run.

Cyclic- Allows watering at a preset interval.

 

 

 OTHER FEATURES

Drip (D) - Allows drip to run by itself or concurrently with another program.

Calendar – Day – Off - This option sets aside any day of the month as a non-watering day.

Contractor default – This is a saved default program that can be accessed later

Master valve/ pump start circuit (MV) - useful for starting a pump or activating a master valve

Programmable delay between stations - ie. For low yielding wells, etc.

Water adjust- Allows user to adjust watering times as percentages from 0-300% on some models.

Valve Test Terminal (VT) - Helps installer sort out firing order of valves after installation

The few features mentioned above will give you an idea of what a controller is capable.  Please consult your manual for more information or go online and check out these features or to download a new replacement manual.  It’s easy to do. For example for Rainbird products use www.rainbird.com, Weathermatic products www.weathermatic.com, Acclima products www.acclima.com, etc.