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How to Install an In-Ground Sprinkler System

An in-ground sprinkler system is easy to install by following these instructions.

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installing an underground sprinkler system

Step 1: Dig a Trench

Using a vibratory plow if possible, dig a trench to lay pipe and wires. Screw the vibratory plow attachment to pipe. Twist electrical wires around the chain (Image 1) — lay them in along with the pipe of the main line. These wires will link the controller with the valves. The vibratory plow has a blade called the bullet (Image 2), which is a bit bigger than the pipe. As it vibrates it cuts the sod and pulls the pipe into the opening. Tip: Be sure to lay pipe at least 6" down into the ground: 1) to avoid contact with the roots zone of the grass, and 2) to avoid contact from an aeration machine if you choose to use one in the future.

Step 2: Trench the Main Line

Trench the main line to the spot of the second valve box. Pull the blade up and detach the plow from the pipe and wires. Dig a hole slightly bigger than the valve box. Tip: When you're digging, always remember to remove the sod first and set it aside carefully, then dig the hole.

installing the sprinkler heads

Step 3: Attach the Valve Manifold

Attach the valve manifold to the main line and all lateral lines that cross it. Note: Poly pipe is best for cold-weather climates. Cut the main line. Slip on the clamps. Attach the manifold. Tighten the clamps to secure it.

installing the valve manifold box

Step 4: Cut the Lateral Pipe

Cut the lateral pipe, slide each side back (Image 1) to make room for the valve manifold. Put one clamp on and attach to the ends of the lateral pipe. Cut and attach the other end of the main pipe (Image 2). Finish trenching the rest of the lines. Warning: When lowering the vibratory plow into a hole next to another pipe, be careful not to hit it with the plow blade or you'll nick the pipe and cause links in the system.

Step 5: Consider a Contractor for Tunneling

For tunneling, hire a contractor for large areas such as the driveway or sidewalk, or you can do it yourself. A contractor will use a pneumatic tool to drive — like a hammer — through the dirt. Note: If you need to tunnel under shorter areas, such as a walkway, you can use a PVC pipe with a nozzle on one end and the water connection on the other end. You'll use water pressure to jet underneath the walkway. Be sure to do this on a seam of the walkway and not on a solid portion, which could weaken the walkway. This works as the perfect conduit.

flush water through system to clean out debris

Step 6: Use Tee Connectors

Where pipes come together use tee connectors. Attach tee connectors to both sides. Mark where you want the adjoining pipe to go. Cut and attach. Hammer into place with a rubber mallet. Tighten the three clamps. After the tee and valve boxes are in place, to secure, drive over them with track of dirt and sod with the vibratory plow.

Step 7: Network Drip Tubing

In garden areas, use a network of drip tubing to create an irrigation system. To do this, first, auger numerous holes. Then, create a network to each garden bed. Tip: Put duct tape over the ends of any piping to avoid dirt from getting in.

Step 8: Flush System, Add Sprinkler Heads

Before adding sprinkler heads, flush water through system to clean out any debris. Tap into the waterline. Attach fitting into the saddle (two types of fittings, your choice) and one into the sprinkler head. Be sure to use a smaller, more flexible piping (Image 1) to go from the main pipe up to the sprinkler head. This type of piping is more manageable and will curve easily. Fill in with some dirt. Level the sprinkler head with level of sod (Image 2). Fill in rest of the dirt and sod. Tip: To maintain an even water-application rate, it's critical to nozzle the heads accordingly. For example, if you have an 180-degree rotary head and a 90-degree head in the same zone, you'll need to be sure to put twice the nozzle on the 180-degree head as you do the 90-degree head. If you're at the end of a pipe run and need to install a sprinkler head, here's what you can do: Take a 90-degree barbed elbow fitting and press it into the pipe, then take a riser fitting and screw it into the pipe and attach the sprinkler head to it (Image 3). Suggestion: If you would like to be able to have your water sprinklers turn off automatically when it's raining, install a wireless rain sensor (Image 4), which has a stack of hydroscopic disks that expand when they get wet, tripping a switch and shutting down the sprinkler system. As the disks dry off, they contract and restore the irrigation sprinkler system. Attach the wireless rain-sensor model to the gutter.

Step 9: Connect Wires to Controller

To get power to the valves, connect wires to controller. One goes to the white or common wire and the other goes to a colored wire. Note: The controller — installed in the garage for this particular project

timer controls length and frequency of waterings

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