How to Adjust Nelson Sprinkler Heads

Preparing the Sprinkler Heads

Nelson sprinkler heads commonly used in home landscapes include the Pro 5500 and Pro 6000 lines, and they lie flush with the ground when not in use and pop up when the sprinkler system is activated. Because adjustments have to be performed while the unit is not activated, propping up each sprinkler head while you work on it is necessary. Pull a sprinkler head's cap upward to raise the sprinkler head until you see a narrow indention that goes all the way around the device. Slide a clamp, which should have been included with the sprinkler system, around the indention. The clamp's pull tab extends outside the housing to keep the sprinkler head propped open.

Making the Adjustment

Nelson offers two cap options with its Pro series; caps of one style can be twisted off, and caps of the other style need to be pried off with a special tool. Twist the cap of each sprinkler head counterclockwise until you can remove its cap. If the caps won't turn, then use the Nelson sprinkler adjustment tool, which was included with the sprinkler system and is available from most landscape supply companies. Place the tool's notched edge under a cap's lip, and pry the cap upward. After removing a sprinkler head's cap, pull out the black, click-set disk in the center of the sprinkler head, flip the disk to the gray side and push it back in place in the sprinkler head, if you want to redirect the spray pattern from a full circle to partial. That task enables the adjustable collars to move. Adjust those collars to direct the sprinkler head's rotation. If a full circle spray pattern is desired, leave the black, click-set disk in place and no adjustments are necessary.

Changing the Nozzles

The arc of the water emitted is an essential piece of sprinkler setup. The far edge of one sprinkler head's water spray should overlap adjacent sprinkler heads' water sprays. A low water arc reduces how far the spray projects while a high arc sends the spray a greater distance. Adjust a sprinkler head's water arc by changing the head's nozzle to one that provides the angle needed. Pull out the nozzle retaining screw from the side of the sprinkler head, and remove the nozzle. After pushing the new nozzle into place, replace the retaining screw.

Testing the Sprinkler Heads

Checking the sprinkler heads' operation after you make adjustments may lead you to fine-tune those adjustments. After removing the clamp so a sprinkler head sinks into its housing, replace the head's cap and turn the water on slowly so it can push air out of the water line. If the sprinkler head's rotation or arc of water isn't correct, then turn off the water and repeat the adjustment and testing steps until the sprinkler head sprays correctly. If the spray is too strong, diffuse it by turning the screw that sits just above the nozzle. Typically, the cap must be removed to allow access to the diffuser screw, which can be turned with the Nelson sprinkler adjustment tool.