Introduction to Automated Irrigation

Alfred Dilluvio, Aqua Turf Irrigation Systems LLC 

For anyone considering the installation of an automated irrigation system, the following should serve as an excellent introduction to the components and general layout. Additionally, this post will highlight the important steps of an irrigation system installation, thereby giving homeowners and property managers an idea of what to expect when they choose to install one.

An irrigation system isn’t too complicated, but there are some components that need to be both identified and explained. Just taking a few moments to become familiar with these parts will allow for a better understanding of what is actually happening when the system is turned on and off. What follows is a list of the most important parts of a system, and an explanation of their function and location.

Main shut off valve for irrigation: This shut off valve is installed on the main line which feeds the system. Depending on the water source, it can be located in several different places. For the majority of residential installations, it will be in the utility area where the water main enters the house. We always affix a Green Aqua Turf label to this component. It is very important to know where it is because if there is ever a leak out on the property, the water can always be shut off here.IMG_2198

Backflow Prevention Device: A backflow device is an important part of any water delivery system that is fed from the potable water supply. It is a device that prevents “backflow,” or the undesirable reversal of flow due to backpressure or backsiphonage. Simply put, it allows water to flow in only one direction. Once water exits the house and goes out to the system, a backflow device will prevent water from flowing back into the municipal (or potable) water supply.825YElectric Valves: These valves open and close at different times, controlling the flow of water to different parts of the system (zones). A cluster of valves is referred to as the manifold. There is always one valve per zone, and usually one master valve placed upstream from the rest of the valves. The master valve is usually located just downstream of the backflow. This valve controls water flow to the entire system (as opposed to just one zone) and protects the system from water loss in the event that there is a leak or stuck valve downstream.

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Valve Box: Located in different spots around the property, these underground boxes house and protect the electric valves. They also contain wire splices and important electrical connections. They allow for easy access to the moving parts buried in the ground. Direct burial irrigation wire and Polyethylene pipe runs to each of these valve boxes.

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Photo courtesy of Rainbird Website

Polyethylene Pipe: Strong flexible pipe used in system design and installation. This polyethylene pipe is used for both the main and lateral lines. The main line comes out of the house and is routed all around the property. Lateral lines branch off the main to bring water to many different areas called zones. There is also a smaller diameter polyethylene pipe with thicker walls and greater flexibility called “funny pipe.” This pipe is used to connect irrigation heads (pop up sprinklers) to the main and lateral lines. It is much more maneuverable and the location of irrigation heads can be manipulated quickly and easily.

8194GnEbqXL._SL1500_Irrigation Emitters (Rotor Heads, Spray Heads, or Drip Emitters): These are the devices that actually deliver water to the landscape. Both rotors and spray heads are spring loaded to a closed position and as pressure builds in the system (due to the flow of water from the source out through the pipe network), these heads pop up and deliver irrigation. Rotors turn slowly to deliver water across a preset arc. Sprays do not turn and deliver water in a fixed pattern. Rotors are typically used to irrigate large lawn areas while sprays are often used for plant beds and tight turf areas where rotors would throw water a bit too far. Drip irrigation is often sub surface, delivering water directly to the root zones via small emitters, that deliver consistent flow rates (regardless of water pressure). Drip irrigation is the most efficient type of irrigation (as there is almost no water loss due to sun or wind).

 

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Controller: The controller stores and keeps track of irrigation programs, start times, and schedules. An irrigation controller, sometimes referred to as a “clock” or “timer,” sends electrical signals to the valves to open and close at different times. While the simplest controllers simply keep time and delivered irrigation according to fixed schedules, new smart irrigation controllers are wifi enabled, receiving consistently reliable weather data and making amendments and schedule adjustments on the fly.

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 Rain Sensor: Device made up of small cork discs which swell in the presence of moisture. These discs rise up and activate a sensor which signals the controller to turn to the off position often displaying the following message (rain sensed).

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Now that we have a basic understanding of important system components, let’s talk about the installation process, and the steps we take to ensure both high quality performance and long term functionality.

After an initial consultation, a system design is proposed. Once agreed upon, an installation crew will arrive and layout the job in accordance with the proposal. Our licensed plumber will identify the water source, tap into the mainline, and run the irrigation line out of the house. A small hole will have to be drilled in order to feed the copper pipe from the basement or utility room. This hole is then sealed and insulated around the pipe. A backflow location must be chosen and the installation must be done in accordance with local code. Once the water delivery line exits the home, and is protected by the backflow, we will install a master valve upstream of the zone valves or manifold. We then connect polyethylene pipe to the zone valves and begin to run the main from this point. That is how we set up the water connection for the system.

Running the mainline is another important part of irrigation system installation. Depending on the nature of the property, we may be able to use a trenching machine that pulls polyethylene pipe through the ground and does so with minimal interruption to the landscape. If the area is wide open enough, the trenching machine can be used. However, if the area is a bit tighter, all trenching will be done manually, burying the lines by hand. Our crews are especially good at doing everything with little to no disruption to the current landscape. In the event that hardscapes must be worked around, our crews cross or go underneath, and they do so carefully, doing everything to ensure unblemished appearance and function. Concrete or stone crossing is something that must be discussed before system installation as crossings can be labor intensive. After the mainline and laterals are installed, the crew sets to work placing irrigation heads in the correct place, ensuring adequate coverage and positioning. Typically, a rotor head is used to cover turf areas and sprays are positioned to cover plantings or tightly manicured turf areas where a rotor will deliver substantial overspray. Sometimes, drip zones are installed for extensive plant areas with specific water requirements. Drip zones are made up of netafim pipe with emitters positioned every 12 inches. They are buried just below the soil for extremely efficient irrigation delivery.

Now that we have discussed the placing of the polyethylene pipe (or the hydraulic components of the system), it is important that we discuss the electrical components and how they are wired. A controller location is chosen and all the irrigation wiring has to be run from this location. The wire goes out to all the valve boxes as each zone wire/the common wire must be connected to the Electric valves. The placing of direct burial wire should be done during the trenching for the irrigation lines. Also, once the controller is placed and the wires are run, a rain sensor can be wired to the controller as well. It is very important that a rain sensor be placed in a good location that is not shielded or sheltered by plant material. This will ensure accurate sensing for the property.

Once all the necessary wires are placed in the controller, to the rain sensor, or in the ground, the earth is restored to grade and the irrigation components are hidden (except for the valve boxes) which can be covered with mulch or artificial turf. It is now time to test the system, make any last adjustments, and program the controller properly (see our next blog post on ideal watering schedules and programming your controller). A system demonstration should then be scheduled where we provide an in depth look at the system, a tutorial of the controller and its use, and a map style zone legend showing the location of each zone.