Programmed irrigation control unit: how the “irrigation programmer” works and how much it costs. What to consider before installation (water pressure and flow rate). Useful tips for the optimal management of garden irrigation.
It is called "control unit" or "programmer" and allows you to automatically manage the start-up and shutdown of the irrigation system. There are many models on the market but basically they can be of two types: electromechanical or electronic. These can be:
- indoor or outdoor
- powered by a battery or the mains
- with installation above ground or in the cockpit
Basically they are "timers" that control one or more solenoid valves for irrigation, closing and opening them according to specific programs. In the most advanced contexts, theirrigation programmerit is connected to a sensor that detects soil moisture so as to suspend irrigation in case of rain.
These systems ofautomatic irrigationthey were born for the maintenance of the lawn but soon they spread dense in every agricultural sector, including hobby gardening and the care of the home garden.
Theirrigation programmerallows you to set the departure time, duration and frequency of irrigations. In the most advanced systems, a group of solenoid valves or each single solenoid valve can be managed in full autonomy, this allows, with a singlecontrol unit, to set different irrigation frequencies. This use is very useful when the same plant must serve both plants that are very resistant to drought and plants with a higher water requirement.
Irrigation control unit: flow and pressure
A discriminating factor in the installation of acontrol unit for irrigationit can be the "water flow". A lower than "ideal" pruning has a negative impact on the efficiency of individual sprinklers with a net reduction in the wetted surface.
What is the flow rate?
The range is given byvolume of water available per unit of time(it is generally expressed in liters per hour). If theirrigation control unitis connected to a tank, in addition to the flow rate, you will also need to calculate the autonomy of the individual water supply.
How many solenoid valves?
Thecontrol unitsthe most common ones can manage up to 25 stations (with as many solenoid valves) while the modelsprofessionalthey can serve up to 50 stations!
In the design of airrigation control unitit is important to consider: the water needs of the plants, the water flow and… also the pressure.
Between pipes, sprinklers and solenoid valves there is onepressure dropalong the net. This "pressure decrease" must be subtracted from the static pressure (the pressure with the shut-off valve closed, that is the pressure of your water system, because it is measured upstream). If you have a very low pressure, the individual sprinklers may be affected until the water is not delivered optimally.
A general rule of thumb to avoid pressure drop is as follows: the diameter of the pipe must not be less than the internal diameter of the valves.
If the pressure is too high, action must be taken upstream of your water system. On the contrary, if the pressure is too high and does not leak into the network of the irrigation system connected to thecontrol unit, you may need to install apressure reducer.
If you have a low pressure problem or want to irrigate your garden with a cistern or tank, you can take advantage of models suitable forfall irrigation that do not require a “minimum pressure” to be able to irrigate.
Connect the irrigation control unit to the tap
In the home garden you may need to connect theirrigation control unit at the tap. In this context, very popular (and cheap) are mechanical programmers.
Amechanical programmerit is installed with a special union which, by means of a connection to the irrigation pipe, connects directly to your tap.
Aprogrammerit can have a single output or two outputs. In the home, onecontrol unit for irrigationwith two outlets, it allows you to easily convey one hose to irrigate the garden and the other to irrigate the garden.
Themechanical programmerperforms the opening and closing of the water flow by means of a motorized and integrated solenoid valve.
Thereirrigation control unitthe electric type, on the other hand, provides for battery or mains power. Generally, the most popular models are powered by one or two 9V batterieselectrical control unitsthey allow you to start more schedules per day or to make weekly schedules with the choice of irrigation days.
As stated, the most advanced models include humidity sensors or pulviometers to adapt irrigation to the frequency of rainfall.
How is it programmed?
Using a rotating ring, a display, a keyboard or ... in some cases via an app on the smartphone via Bluetooth or even Wi Fi with remote management (useful for a beach house!).
Orbit irrigation control unit
Among the most popular models for amateur use there is the “Orbit” control unit or programmer. It is battery operated, you can buy it on Amazon with 42 euros and free shipping costs. It is an interesting product as it allows you to use 3 independent programs with 4 starts, this would allow you to perform up to 12 irrigations in one day. It also has a function that makes the irrigation slip by 48 or 72 hours in case of rain.
For all product info, I invite you to visit the official page: Orbit Pocket 6 Zone
Please note: the6 zone obrit irrigation control unitit is certainly the most popular but not the cheapest, on the market there are also more essential models that can be bought with 20 euros.