Hunter Industries has manufactured a variety of sprinkler heads. However, it has discontinued some of its most common designs, leaving many customers without proper replacement heads for their sprinklers. One of these heads, the G-type, was phased out in the early 2000s. Customers with these heads sometimes have no idea how to adjust this unique sprinkler head. Luckily, many of the company's sprinkler heads are adjusted in the same way. Because of this, instructions to adjust these heads can still be found.
Switch on your sprinklers using the electronic controller for your system. Most controllers require you to select a specific station, and then manually switch it on. Although you will get wet while adjusting the heads, it is important to have the heads on while you are adjusting them so you can see firsthand what effects your adjustments are having.
Find the right edge of each sprinkler head's arc by turning the top of the head all the way to the left, and then all the way to the right. If this edge of the arc is not where you want it to be, the only way to adjust it is to turn the base of the head using the channel locks. Check your adjustment by turning the top of the head left, and then right.
Find the left edge of each sprinkler head's arc by turning the top of the head all the way to the right, and then all the way to the left. To adjust this edge of the arc, insert the key end of the Hunter tool (it looks like a "T") into the slot just below and to the left of the little arrow on the top of the head. Turn the tool to the left to decrease the arc, and to the right to increase the arc. Remember to check your adjustments by turning the head right, and then left.
Adjust the spray pattern of the sprinkler's jet of water by inserting the Hunter tool's hex key into the arrow on the top of the head. Turning to the left will make the stream of water spray farther, while turning to the right will make the stream spray a shorter but broaden water spray. Be careful not to turn it too far to the left or right, or the screw will loosen and the nozzle will pop out of the sprinkler.
Shut off the sprinklers with the electronic controller. In most cases, switching the system to "off," and then setting it to "automatic schedule" is appropriate.