Step by step irrigation installation 3

Now that your drawing is divided into sections, you can take them one at a time. You'll need to plan the sprinkler locations so that the spray from one sprinkler will reach to the other sprinkler location. This is called 'head-to-head' spacing or coverage. You'll need to check the distance of throw and spray pattern of each type of head to do this part of your layout.

REMEMBER:

Choose "small to medium" area sprinklers for areas smaller than 25 by 25 feet.
Choose "medium to large" area sprinklers for areas larger than 25 by 25 feet.

Draw in your sprinklers starting at the corners, then if needed, draw in sprinklers around the edges of the area. If needed, draw sprinklers in the middle. Keep sprinklers evently spaced and remember to overlap head-to-head.

Odd shaped areas can be effectively covered using adjustable pattern nozzles that adjust from 0 to 360 degrees.

Narrow strips can be covered using end, side or center strip nozzles.

Head-toHead Coverage

Now that you have your sprinklers drawn in and you have found out your home's water cpacity (GPM), you will need to determine how many valves it will take to operate them. You need to figure out how many sprinklers can be run at one time by your home's GPM. System design is restricted to 24 GPM maximum.

Now that you have figured how many zones you need, you know how many valves to install. Remember, you need a valve to control each zone. When installed, valves are usually grouped together into something called a "valve manifold". A typical manifold will have 2 to 6 valves. Sometimes more valves are required. You might have a manifold for your front yard and one for your back yard.

There are two types of pipe commonly used in sprinkler installations, PVC pipe or Poly Pipe. Once you have your pipe drawn on your layout just count how many feet you need to buy. Order some extra in case of minor cutting mistakes.

Wrong way to lay pipe

Right way to lay pipe

PVC PIPE CLASS 125 / CLASS
Max GPM Flow	Pipe Size	Valve Size
0-10	3/4"	3/4"
>10-15	1"	1"
>15-24	1 1/4"	1"

POLY PIPE / GALVANIZED PIPE
Max GPM Flow	Pipe Size	Valve Size
0-8	3/4"	3/4"
>8-12	1"	1"
>12-22	1 1/4"	1"

Use this chart to size your pipe according to GPM needed for each zone. Label the pipe on your drawing. remember to size your connecting pipe to the largest zone.

There are a variety of timers and controllers available for your system. You will need one with a "station" for each of your valves. You might even purchase one with extra stations in-case you add to your system at another time. Locate your timer in a place that is easy to get to, like the garage or basemen, near a 110 volt outlet. To wire a timer use coated irrigation wire which is rated for underground burial. Buy irrigation wire with one more strand than the number of valves you will be wiring.

Example: If you have 4 valves, buy 5-strand wire, one strand per valve and one "common wire".

Get enought wire to rach from the timer location to the farthest valve, then add a few feet just to be safe. The connections at the valves should be made with water tight connectors. Two connectors for each valve.