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How to Install a Home Sprinkler System

                

The installation of a sprinkler system is both labor intensive and requires attention to detail, as incorrect placement or spacing could lead to serious problems and much more work down the line. This article serves as a primer that can be referenced if you are considering installing a sprinkler system. 

Also see our post below for the layout guidelines to a sprinkler system!

Connecting the Water Supply

In order to supply water to the sprinkler system, the main water line will need to be tapped into. In some cases, the line was installed with a stub-out specifically for future irrigation. If this is the case, the back-flow prevention device can be installed at the stub-out. This is rapidly becoming the standard for new construction projects. In cases where no stub-out was provided, the main line will need to be tapped into with a compression tee and a stub-out installed. The water line is usually found by locating the water meter on the property, following the pipe direction for a couple of feet and digging down. If it is a cold weather climate, the main line can usually be found 3-5 feet deep. Warmer weather climates will tend to have the main line anywhere from 1-3 feet underground.

Marking the Sprinkler Head Positions

The next step for installation is mapping out the layout onto the lawn. There are a number of different methods for marking the layout. In most cases, the sprinkler heads are marked using wooden stakes or marking flags and the pipe network is designated using either string or marking paint. While the paint applicator and paint may be costlier, it can also help avoid issues with uneven or curved trenches.  This is an important step because it allows you to physically check to ensure that the distances between the sprinkler heads are correct, and that there will be no conflict when setting the pipes. If the initial layout was correct, the heads will be within the maximum distance of each other, providing total coverage. If a redesign is needed, it is best to take the time to do it now before the trenching and installation is finished.

Preparing for Trenching

It is advisable at this point to contact the utility locator service for the state. The name varies by state, but their intentions are all the same: to notify people of utility lines that may be running under their property. Having the center send someone out to mark the property is required in some states, but should be done in all circumstances. A worker will mark the lines on the surface using colored spray paint to indicate what kind of utility line it is. Using these markings as guidelines can prevent the damaging of a utility line while digging the trenches for the sprinkler pipes. If further incentive is needed, damaging a utility line and/or not having contacted a utility locator to mark the property usually results in a significant fine – and in some cases, a criminal charge.

If the marked utility lines interfere with the planned layout of the sprinkler system, adjustments will be needed. This may require a minor change in the branching of a zone, or to redesign the zones entirely.

Digging the Trenches

Once the property has been checked by the locator service and any lines have been marked, the trenching process can begin. Although the trenching process can be done by hand using trenching shovels, it is by far more common currently to use a automatic trencher. Plumbing or sprinkler suppliers may carry a trencher that can be rented as part of purchasing the necessary parts. If not at a supplier, many heavy equipment rental companies will have a selection of trenchers available. In comparison to digging the trenches by hand, the automatic trencher is far more efficient.

For warmer climates, the piping will only need to be 4-6 inches deep. In colder climates that can experience sudden hard freezes, it is better for the pipes to be deeper underground, anywhere from 8-12 inches deep. The deeper the pipes are, the less likely they are to freeze. When digging the trenches, they should be as narrow as possible, in most cases only 3 inches wide.

Installing the Controller and Valves

After trenching is complete, the valve manifold should be installed. Run pipe from the main line down to the area where the valve manifold will be. The next section includes information on connecting the two major pipe types to fixtures, and it may be advisable to review it before attempting to attach the manifold to the pipe. In most circumstances, installing the manifold so the valves are at ground level will be sufficient, however if using anti-siphon valves they must be 6 – 12 inches above the highest sprinkler head so the back-flow prevention systems work.

The sprinkler controller is essentially the brain of the system and is usually mounted on an exterior wall of the home near the sprinkler valves. This device will control the activation and shutdown of each valve and their associated zone.

Assembling the Pipes and Wiring

Once the controller and valves are installed, the piping can be assembled. In general, it is a good idea to start from the valve manifold and piece together the pipe system from the manifold out to the individual branches of the system. If the system was designed with PVC pipe in mind, the standard tool for connecting pipes and fittings is PVC cement. PVC primer can also be used, but it is not always required. It is best to check local plumbing codes on the requirement of using PVC primer. Using PVC cement (and primer, if desired), connect the pipes to their fittings and expand the grid out from the source to the end of each branch. When installing, it is important to try to avoid allowing dirt from the trenches into the pipes being assembled. If the system was designed to use PE pipe, the fittings are inserted into the PE pipe and stainless steel clamp is tightened around the PE pipe to keep the fittings in place. A rapidly growing alternative is to use specific fittings from Blazing Products that have been specifically designed to be quick to install in PE pipe and do not require clamps.

If considerations are being taken due to the system being installed in a cold climate, now is the time to install them. If using drain valves, this will require installing an additional tee for each drain valve. if an air compressor adapter was planned, the drain valves are not required but can still be used. The adapter should be installed before the valve manifold when attaching the valves.

Once the grid is finished and connected to the water supply, but before the sprinkler heads are installed, it is important to flush the system to clear the pipes of any dirt that may have found its way into the piping. After turning on the water for each zone for about two minutes, the pipes should be clear and the trenches can be refilled.

The wiring of the system will extend from the controller down to the side of the residence and into the trenches until it reaches the valve manifold. As such, it is important to use 18-gauge wire that can be buried. If installing a system that uses multiple valves, be sure to order wiring that has strands equal to the number of valves plus one. The wire will have one strand that connects to each individual valve back to the controller, and the remaining strand – referred to as the common wire – connects all of the valves to the controller in a single chain.

Filling the Trenches and Attaching the Sprinkler Heads

At this point, it is recommended to begin refilling the trenches. It is not necessary to completely fill the trenches quite yet, but rather only to cover the pipes. Leave space near the sprinkler risers to install the heads. Once the pipes are buried, it is recommended to do another flush of the system to ensure that there are no blockages. Leave the water on in each zone for around 2-3 minutes to ensure thorough flushing. After the flushing process is complete, the sprinkler heads can be installed. Ensure that the proper nozzles are being used and that they are adjusted to match the design of the system. Once the heads are installed, activate each zone again to ensure the sprinkler heads are all working. Adjust the spray patterns on each nozzle to ensure they are overlapping with adjacent sprinkler heads. It is also necessary to adjust them if they are spraying the house, sidewalks or other areas that should not be watered. If something is wrong, you may have to dig up the pipe for the particular area and re-check the connection. If nothing went wrong, then the installation is complete.

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Sprinkler Season is Upon Us!

HOW TO LAY OUT A HOME SPRINKLER SYSTEM

                

Possibly the most difficult step in implementing a home sprinkler system is settling on a layout to use. Several variables have to be taken into account, such as the water pressure on the property, the overall shape of the lawn and designating the layout of watering zones on the property. This article should provide some general guidelines that can help make designing the layout less of an ordeal.

GAUGING WATER PRESSURE AND CAPACITY

The first step in the design of an irrigation system needs to be checking the main water supply’s output and pressure. The key elements of the irrigation design will depend on the water capacity and pressure of the supply line. If the water is coming through at over 30 psi, rotor sprinkler systems become an option. Less than 30 pounds of pressure means that a pop-up spray system will be ideal, as misting – where water is being forced through the spray heads at too high a pressure – becomes an issue at pressures exceeding 30 psi.

For measuring the flow of water, a simple mathematical equation should provide the answer. Take a 5 gallon bucket and time how long it takes for the bucket to fill from the water line. Divide 60 by the number of seconds it took, and then multiply that number by 5 – the number of gallons – to get the gallons per minute. As an example: filling the 5 gallon bucket takes 15 seconds. 60 divided by 15 is 4. 4 multiplied by 5 equals 20, so the flow of the main line is 20 gallons per minute.

MAPPING THE YARD

The next step in the designing process is drawing a map of the area that will be watered. It is important to note the different things in the yard such as trees or shrubs, where the yard meets the sidewalk, flower beds or other features of the lawn. It is also important to note the location of the main water supply line on the map.

When designing the layout for the system it is a good idea to factor in the sprinkler head ranges you will need to cover all sections of the lawn. The sprinklers should be spaced so that the radius of one head reaches the next sprinkler in the zone. This is called “head-to-head spacing” and is used to make an efficient watering grid for the sprinkler system. Using head-to-head spacing prevents watering gaps in the yard, which would lead to patches of grass that would not be fully watered – if watered at all. After mapping the sprinkler heads for the system, be sure to note how many heads were drawn on the plan and which spray arcs they were, so the proper parts can be purchased later on.

Designing zones may end up being one of the more complicated steps in designing a home sprinkler system. It is important to keep areas such as gardens and flowerbeds separate from the main lawn area when forming groups for zones, as they often require their own specially tailored series of sprinkler heads.

When designating the watering zones, it is important to take into account the amount of water each zone will be using. As a rule of thumb, zones using 3/4-inch supply pipe for the yard should not exceed 13 gpm and zones using 1-inch supply pipe should not exceed 18 gpm. This will require knowledge of the flow capacities of the sprinkler heads being used, so it is a good idea to consult manufacturer information for the sprinklers you will be using.

SELECTING CONTROL VALVES

Once the zones have been mapped out, the control valves need to be selected. Each zone will be controlled by an individual valve that opens and closes for the specific zone based on instructions from the controller or timer. The specific valves used will be determined by the water pressure and flow of the supply line as well as specific plumbing regulations for the city. Most cities will require that a valve be installed with a back-flow prevention device that is either installed before the valve manifold or is built in to the valve itself. The most commonly used valves and back-flow preventer for a residential system are a diaphragm valve paired with a pressure or atmospheric vacuum breaker.

It is also necessary to map out the location of the valves. In the case of residential systems, it is increasingly common for homeowners or contractors to group the valves together in a manifold that is close to the main supply line. The grouped valves are usually covered by what is known as a valve box, a protective plastic shield that keeps valves out of sight and prevents dirt from entering and damaging the valves.

MAPPING THE PIPES

After mapping out the sprinkler heads and control valves, mapping out the pipes is the next step. This is done on a zone by zone basis. Starting from the sprinkler head in the zone that is furthest from the valves, draw a line that leads back to the valve for the zone. In many cases, it will not be feasible to connect all the sprinkler heads through a single line of pipe. In zones where the sprinkler heads are arranged in a grid, for example, it is more efficient to set up a main line that branches off into smaller lines that provide an even water distribution and preventing loss of pressure. The placement of the main line for the valve is important as well. If the branches are too long, sprinklers at the end of the branch are going to be watering inefficiently due to the pressure loss. In zones that consist of a single line of sprinkler heads, such as with a line of shrubs, only one line of pipe is required.

Be sure to note the measurements for the lengths of pipe that have been mapped out, as well as noting the number and types of fittings (the points where pipes intersect or where heads will be installed) in the design. It is important to take into account the type of pipe that will be used for the system. Schedule 40 PVC or Polyethylene pipe are the most common choices for piping in a home sprinkler system.

By far, the most often used pipe in a sprinkler system is PVC. Polyvinyl chloride piping is inexpensive, very durable and very easy to assemble. PVC piping comes at differently rated strength levels, and some local codes may require a certain strength rating on pipe used for home irrigation and sprinkler systems. The strength of the PVC pipe will determine the pressure of the sprinkler system it can be installed in.

Polyethylene tubing is black, flexible pipe that is used primarily in areas with cold weather. It is becoming increasingly common as an alternative to PVC. PE pipe is more resistant to freezing than PVC pipe is and can be used in low-pressure systems. PE piping has a generally lower pressure threshold than PVC and is not suited for high-pressure water systems, however as most residential systems do not reach 100 psi, it is a completely viable alternative.

COLD-WEATHER DESIGN CONSIDERATION

In areas of cold climate, it will be required to winterize the system each year when the temperature drops in order to prevent damage to the system. This will require consideration of winterizing options such as drain valves or using a compression pump. If planning to use manual valves, be sure to mark the locations on the grid. They will need to be installed at all low points in the system as well as the ends of each zone branch. With automatic valves, they should be placed at 50-foot intervals and at every low point as well. If planning to use an air compressor for the system, it is generally a good idea to plan for an adapter right before the valves in the valve manifold that an air compressor can be attached to.

PURCHASING THE PARTS

Once you have a list of all the parts that will be needed, you can go to www.PlumbersStock.com with the parts list and purchase or order the parts you will need. Once the parts arrive, the installation process can begin.