irrigation controllers 0903

7/29/2019 Irrigation Controllers 0903

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IRRIGATION CONTROLLERS

FOR THE HOMEOWNER

Recommended Water Saving Features

Watertoo precious to waste!

CONTROLLER

CONTROLLER


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For copies of this brochure call the California Department of Water Resources

Bulletins and Reports section at (916) 653-1097.


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Foreword

This brochure is a cooperative effort sponsored by membersof both the water and landscape industry to promote

efficient landscape water use. The purpose of this brochureis to highlight important irrigation controller features thatallow for proper irrigation scheduling. Since many peopleare somewhat mystified or intimidated by these devices,hopefully, this brochure will help when making the deci-sion of which controller to obtain. The main point to keepin mind is that the key to watering efficiently is to obtaina controller that can handle diverse landscape and weathersituations and then to program it properly. This message isso important; it is repeated again in the text.

We encourage you to contact your local water agency orlandscape company to obtain more information on how toimprove landscape water use efficiency. For any technicalassistance you may need with your controller, contact themanufacturer.


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Importance of Irrigation Controllers

A large part of our household water use goes to wateringour landscape and many households rely on automaticirrigation systems to accomplish this. One of the mostimportant components of an automatic irrigation systemis the irrigation controller (also called a timer or clock).The controller turns the irrigation system on and off atthe times you select. In other words, the controllercontrols the irrigation system and you control the control-

ler. Having a controller with certain minimum perfor-mance capabilities is vital to efficient watering. The rightcontroller, properly scheduled, can result in significantwater savings and lower water bills.

How Does a Controller Work?

An automatic irrigation system is a collection of pipes,tubing, valves, sprinkler heads, and circuitry used toirrigate a landscape. Automatic valves (also called stationsor zones), which control the flow of water todifferent parts of the landscape, open and shut upon a

signal from the controller. For example, there may beone valve that controls the water flow to somegroundcover, another valve for some shrubs and anothervalve for the lawn. Once programmed, the controllerdetermines when, how often, and how long each valve isopen. It controls how much water goes where and whenin your landscape based upon your instructions. The more

programming flexibility the controller has, the moreefficiently water can be applied to the landscape.

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Why Certain Controller Features are Important

The key to watering efficiently is to obtain a controller

that can handle diverse landscape and weathersituations and then to program it properly to meetyour plants water needs. Lets imagine you have a frontyard with three valves that control the water flow to asloped lawn area, to several trees, and to a groundcoverarea. You desire to water the lawn every third day for theentire month in three short time intervals of five minutes

each and want a 30-minute break between watering toavoid runoff from the slope. You also desire to water thetrees, which are on a drip system, once a month for twohours. Next, you want to water the groundcover once aweek for 30 minutes. Finally, you dont want to water ifit is raining. To accomplish this, your controller wouldneed the following features: 1) three independent pro-

grams, 2) 120 minute station run times, 3) three starttimes per program, 4) interval program capability to 30days, and 5) rain shut-off device capability (the actualrain shut-off device needs to be purchased separately).

Important Water Saving Features

The recommended minimum hardware features for acontroller when water efficiency is a priority include:

Hardware Features Three independent programs

Station run times from one to 200 minutes

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Three start times per program Odd/even, weekly and interval program capability up

to 30 days

Water budgeting from 0-200%, in 10% increments, byprogram

365 day calendar, adjusted for leap year Non-volatile memory or battery back-up Off, Auto, and Manual operation modes

without disturbing programming Rain shut-off device capability

Diagnostic circuitry to notify homeowner when stationis shorted or a power failure has occurred

The above features, discussed in more detail below, areimportant because they give you the ability to properlymanage your landscape watering.

Multiple independent programs allow watering differentparts of the yard on different days. Station run timesdetermine the upper and lower limit on how long an areacan be watered. While watering times are usually inminutes, a few controllers are capable of assigning runtimes in seconds (for potted plants) and hours for dripapplications. Multiple start times allow for repeat

watering in the same area on the same day. Odd/evenweekly and interval program capability allows forflexibility in deciding what days to water. For example, a30-day calendar would allow watering a large tree once amonth. Water budgeting (also known as a percentswitch) allows for an increase or decrease in station runtimes by a certain percent. For example, during a cool

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AUTOMATIC IRRIGATION SYSTEM

Drip/Bubbler Emitters


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Groundcover Spray Heads

Sprinkler Heads

Pressure Reducer for dripline down to 20-30 psi

Control & Anti Siphon Valves

RainSensor

Irrigation

Controller(timer, clock)

WaterSupply

Filter

Pressure Reducerdown to 60 psi


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spell, you may want to decrease watering time by 10% forall programs. This feature allows for the changing of allstation run times within a given program in one easy

step. 365-day calendar allows for the tracking of thenumber of days in each month throughout the year.Non-volatile memory retains the set program in case ofa power failure. However, the set start watering times arestill affected. For example, a four-hour power failurewhere the watering times are set to start at 6 a.m. wouldresult in 10 a.m. start. A battery back-up is recom-

mended to retain the 6 a.m. watering time. Controllerswith only volatile memories would both lose their setprogram and have the watering start time affected. Forcontrollers with volatile memories, a battery back-upwould retain both the set program and the set wateringtimes. Rain shut-off device capability (and rain shut-off device) is used to automatically override the call for

water during rain events. (The actual rain shut-off deviceneeds to be purchased separately since it is not includedwith the controller.) Diagnostic circuitry to notifyhomeowner when a station is shorted or a power failurehas occurred is useful so that the controller can bechecked for any changes or problems as soon as possible.

In addition to the above hardware, programming instruc-tions, technical support phone numbers, and irrigationscheduling information are important resource tools.Check with your local water utility, irrigation supplycompany, or landscape professional for local wateringguidelines.

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Optional Controller Features

Besides the above mentioned recommended controller

features, several desirable but optional features includepause times and soak cycles. The pause timefeature allows for some time to elapse before wateringdifferent stations within a program. This feature allowstime for a control valve to completely close before thenext valve opens ensuring more uniform pressure andthus better uniformity of coverage. For those on well

water, this feature may allow time for the level in the wellto recover before the next irrigation cycle. The soakcycle allows for short, multiple watering cycles. Thisfeature can be used either before a normal irrigation cycleto wet the soil to break the soil surface tension to reducerunoff or for multiple, short watering of a given area.

Controller Warranty

Ask about the warranty on any controller you are consid-ering. The length of a product warranty is often linked toquality and many controller manufactures are offering

warranties in the 2-5 year range: the longer, the better.

Other Important Components of an Efficient Irrigation System

Besides obtaining an irrigation controller with the recom-

mended features, there are other irrigation components

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that should be used with irrigation systems to saveadditional water. Control valves control the flow of waterto different parts of the landscape and are used for the

separate watering of plants with different watering needs.Check valves can be installed in sprinkler heads toprevent water from draining out of the irrigation linewhen the water is turned off and are most useful on slopedlandscapes. Rain shutoff devices can be wired to acontroller to shut off the system when it is raining.Moisture sensors can be wired to control valves to

override the call for water if they sense that enoughmoisture is already present in the soil. Moisture sensors,therefore, monitor the irrigation schedule for overwatering. Drip or bubbler irrigation can be used toirrigate slowly and minimize or eliminate evaporation,runoff and overspray. Finally, low precipitation spray,stream, and sprinkler heads with matching precipitation

rates can dramatically improve efficiency.

It is important to note that automatic irrigation systems,if not properly managed, can waste a lot of water. Alwaysbe mindful that YOU are the brains behind yourirrigation system scheduling and YOU control the con-troller.

The Importance of Proper Irrigation Scheduling

Plants require the most water during the summer andlittle or no water in the winter. After July, plants need

less water each month, and by November, often little orno irrigation is required until March or April. Then, plant

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water needs increase each month through July. The chartbelow compares the typical month to month averagepercentage changes in your landscapes water require-

ment to the July requirement. For example, thelandscapes water requirement in May is twice that ofApril but only 60% of the July requirement. This chartdemonstrates the importance of regularly changingyour irrigation schedule. Note that by the end ofSeptember, your landscape will need only about halfof the water it needed in July. Since this chart is based

upon the change by month in a plants water need, localprecipitation will, of course, affect how much supplemen-tal irrigation is needed. Check with your local wateragency or Cooperative Extension office for specificmonthly water requirements for your landscape.

Typical Monthly Percentage Comparison of Landscape WaterNeed Using July as Basis

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

0 0 5 30 60 90 100 90 60 30 5 0

Other Water Saving Landscape PracticesBesides proper irrigation system design and scheduling,water use efficiency in the landscape can also be in-creased through appropriate use of plant material, soilpreparation, and proper horticultural practices (mainte-nance).

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Extensive use of plants suited for the climate of theregion should be considered for your landscape. Plantsshould be grouped, as much as practical, according to

their water requirements. Proper horticultural practicesthat include regular pruning, weeding, lawn aeratingand dethatching, and the use of mulches and fertilizersshould be followed.

For more detailed information regarding water savingopportunities in the landscape contact your local oppor-

tunities in the landscape contact your local water agency,irrigations supply store, or landscape professional.

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SAMPLE WATER SCHEDULE

The chart below shows a sample watering schedule. Youcan increase or decrease the amount of water applied to thelandscape by changing either the number of start times perday, the number of minutes per day, or the number ofwatering days per week. Note in this example the wateringtimes stay the same but the number of watering days perweek, change during the year. Also, note no watering is

shown for the winter months. To determine the appropri-ate watering schedules for your area, contact your localwater agency or landscape professional. Keep your sched-ule in your controller for easy references.

Sample Water Schedule

Plant Sprinkler Starts Minutes Number of Watering Days per WeekType Type per day per day Fall and Spring Summer

2212

lawn spraygroundcover spray shrubsdrip trees drip

773030

2.5.50

311.5


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Sponsoring AgenciesCalifornia Department of Water Resources

California Landscape Contractor AssociationCalifornia Urban Water Conservation CouncilCity of Austin, TexasCity of Santa BarbaraEast Bay Municipal Utility DistrictIrrigation Association

Johnson County Water District #1New Mexico Office of the State EngineerSanta Clara Valley Water District

Southern Nevada Water AuthorityTacoma Water, WashingtonUnited States Bureau of ReclamationUnited States Environmental Protection Agency

This brochure was reprinted by California Department of Water Resources inSeptember 2003. A copy of this brochure is also available in PDF format at

www.owue.water.ca.gov/landscape/pubs/pubs.cfm. Additional information is

also available at:Web site: www.owue.water.ca.gov/landscape

E-mail: [email protected]: (916) 651-9676

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