We are continuing series of posts about underground sprinklers in residential lines. We have covered the planning and ordering of materials. This post will be about installing your underground sprinkler system. Underground sprinkler installation is relatively straightforward provided that you follow a set of rules and guidelines as follows.
Install the manifold. First, turn off the water to the house. Cut a 1 1/4 inch section from your service pipe and install a T fitting. Several special tees are available for cutting into lines. Ask at a local hardware store.
Install a length of pipe and a shutoff valve in a valve box. The shutoff valve is usually a gate valve and allows you to turn off the water to the sprinkler system without turning off the house water. Once the valve is turned off, you can turn the house water back on. Run lines to the manifold location and install the control valves. It is usually easiest to assemble the manifold at the shop bench, Then carry it to the site and install it. Close the valves, open the shut off valve, and test the manifold for leaks.
If you are using automatic valves and an electric timer, install it according to the manufacturer’s instructions, and lay the connecting wire to the valves. Most timers run on a voltage that is low enough, 24 V, to let you bury the wire directly without enclosing it in conduit. Position the timer where it is protected from sun and rain and it’s close to an electrical outlet; the garage is ideal. The position of the timer may influence the location of your control valves.
Mark the layout on the lawn. Drive a stake into the ground at each sprinkler head location. Sprinkle agricultural lime on the ground to mark where trenches are to be dug.
Dig trenches. Next to your pipe layout, use of a spade or rent a trencher to dig trenches. Make the trenches at least 8 inches deep.
Now you are ready to install the pipe, risers and sprinkler heads. Our next post will cover the details associated with this step. Check all of your measurements, especially before digging to ensure that all of your trenches will be in the correct location.
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