Irrigation Controllers

The Brains of the Operation

Controllers are effectively the “brains” of the irrigation system

Used to carry out watering schedules automatically

Irrigation systems are typically 24 volts

Controllers

Programmed to start watering at specific stations . . .

At selected times and . . .And for predetermined durations

(length of times)

Controllers

Large selections available . . . Fits almost all irrigation needs . . .And most budgets

Types of Controllers

Digital Controller or Solid State Hybrid ControllerElectromechanical Controller Hydraulic Controllers

Digital/Solid State Controllers

Computerized Digital readout display w/ keyboardNo moving partsAccurate

Digital/Solid State Controllers

Can be complicated to programBattery backup – can retain program

for several hours to days depending upon manufacture

Can be remotely operated

Hybrid Controllers

Combines solid state circuitry with mechanical type controls

Considered more “user friendly”Mechanical “user interface” allows

for easier use . . .Integrated with solid state

technology

Hybrid Controllers

Knobs, switches and sliders are the moving parts

AccurateBattery backup

Hybrid Controllers

Hybrid Modular Controllers

Electromechanical Controllers

OlderMechanical technology containing . .

. Motors and gears . . . Wheels . . . Dials and pins

Electromechanical Controllers

Considered “user friendly”Does not loose program in power

outagesInaccurate – give or take 5+ minutes

Hydraulic Controllers

Connected to valves by small tubing carrying water under pressure…

When the pressure is released, the valves open…

When the pressure is reapplied, the valves close

Hydraulic Controllers

In many cases, the valves are in the bottom oh the individual heads

Typical in large heads used in sports turf applications

Controller PlacementIndoor Controllers Have external transformers . . .On power cord (wall wart)Unsuitable for outdoor use

Outdoor Controller Placement

Outdoor Controllers Cases are water-tightInternal transformersMust be "hard wired" using 110v

Outdoor Controller Placement

When used indoors a “pig tail” can be attached

Outdoor Controller Placement

Correct installationInappropriate installation

Outdoor Controller Placement

Should be located within “eye shot” of the valves they control . . .

Whenever possible Should never be located within the

spray of the irrigation heads

Controller Features

Versatility is typically a function of cost with irrigation controllers . . .

More features . . . More moneyTypically, more expensive

controllers have more capabilities

Controller Stations

A station in a controller is tied directly to one valve circuit or zone . . .

And is numbered 1, 2, 3, etc. The term “station” can also be

considered as one valve and the heads connected to it

Programs

A program is a set of watering instructions or a watering schedule, including . . .

Days to be watered . . .Start times . . .Stop times . . .Run times or durations

Programs

Controllers with multiple programs allow increased flexibility . . .

Also allowing multiple start/run times per station . . .

Program are continuous from start to finish

Start Times

The number of times a controller can signal the stations per day . . .

Cheaper controllers have fewer start times

Start Times

Multiple start times allow for greater flexibility . . .

Particularly in specialized settings ex.:

newly planted turfslope plantingsgreenhouses and mist houses

Watering Cycles

A complete set of irrigation instructions is implemented during a cycle, including . . .

Start times Run times Run days

Watering Cycles

Typical watering cycles are 7 days, 14 days and 15 days

7 day watering cycles limit possible programs

7 day clocks allow for daily watering but not every other day or every 3rd day

Watering Cycles

14 day and 15 day watering cycles allow greater flexibility for programming

14 day clocks allow for watering every day or every other day

15 day clocks allow for every day watering, every 3rd day or every 5th day

Run Days

Selected days the irrigation program will operate

Some controllers allow choices of . . . every day . . .every other day . . .every third day or . . .selected days

Run Days

Many controllers default to an every day watering cycle in the event of power / battery failures

Station Run Times

Most controllers have run times from 1 to 120 minutes

Many controllers allow stations to run in minutes or hours for greater flexibility

Station Run Times

Specialized controllers have shorter run times of 1 to 60 seconds . . .

Or for several hours for agricultural uses . . .

Drip irrigation and . . .Greenhouse / nursery production

Manual Control Switch

Allows the operator to override the cycle and manually control the watering process

Used when testing stationsAlso used to manually irrigate after

new planting installations . . .or any ole time

System On / Off Switches

Allows the entire controller to be turned off without loosing the irrigation program . . .

For maintenance reasons or . . .In the event of rain

Global-Percentage Adjustment

AKA seasonal adjustment switch . . .Allows the watering run times to be

adjusted up or down . . . Across all run times in a program . . .Water budgeting by program from 0

to 300% in 1% increments

Global-Percentage Adjustment

Irrigation programs are developed based on 100% of the irrigation requirements

Allows for adjustments up in extremely hot, dry weather or . . .

Adjusted down as the water requirements are reduced by cool, damp weather

Remote Control Systems

Satellite control systems are programmed at a central computer

Can be tied into any number of irrigation controllers

Cellular remote systemsInternet connections

Remote Control Systems

Rain Sensors

Tied directly into irrigation controllers

Set to shut off controllers at predetermined amounts of rainfall

Some older controllers must be manually restarted

Soil Moisture Sensors

Placed in the soil within the root zone of plants or turf . . .

Tied directly into the irrigation controller . . .

Shuts off the controller when soil achieves predetermined soil moisture levels

Soil Moisture Sensors

Wire

Typically copperAnalogous to the pipe used in

irrigationSmaller wire carries a smaller flowSmaller wire offers greater

resistanceKinda like friction loss

WireAs with sprinklers, adequate voltage

must be maintained over the entire length of the run to properly operate the furthest valves

Should be covered by 18" of soilWhen possible placed under

irrigation service line pipingLoosely snake the wire in the trench

Basic Electrical Terms

Volt (V) – unit of electrical pressureAnalogous to water pressureAmp (A) – unit of measure for the

flow of electronsAnalogous to water flow

Basic Electrical Terms

Watts (W) – an expression of powerVolts x Amps = WattsVoltage Transformer – reduces

voltage from 120V to 24VAnalogous to a pressure regulator

Short

Typically caused by a nick in the wire insulation . . .

Or a loose connectionAllows the electrons to “leak”

out . . .Causes an inadequate voltage

supply at the valves

Control Wire or Hot Wire

Carries current out to the irrigation valve from the controller

Each valve should be individually connected to the controller

Can be most any color

Common Wire

Returns current from the irrigation valve back to the irrigation controller

Common wire can link all valves in series to the controller

Usually white

Wire Sizing

The wire used to connect irrigation valves to irrigation controllers is typically a buriable type referred to as "underground feed" (UF)

Thermostat wire or door bell wire is NOT acceptable for direct burial

Wire Sizing

Determine the length of the run – valve to clock

Determine static water pressureGreater static pressure requires

larger wire to overcome higher water pressure resistance when opening the solenoid

Wire Sizing

Use a wire sizing chart for the appropriate static pressure to determine the appropriate wire size

For most residential applications, 14 gauge wire is adequate

Expansion Coils

Expansion coils are coils formed in the wire at the irrigation valves

They allow the wires to expand and contract without pulling apart at the connections

Expansion Coils

Expansion coils allow the valve to be serviced without having to cut controller wires to gain access

8 or 9 wraps around 1/2” pipe

Dry Splice Connectors

Used to connect two to several wires in underground vaults . . .

And at valve connections . . .Reduce or eliminates corrosion at

connections . . . Reduces chances of faulty

connections occurring