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