The precise distance, or radius, of a sprinkler system’s spray pattern is crucial for efficient lawn care. Adjusting this distance ensures water is applied uniformly without being wasted on sidewalks or pavement, preventing dry spots and excessive runoff. Homeowners can perform these simple modifications to optimize irrigation performance, leading to a healthier lawn and potentially lower water bills.
Identifying Sprinkler Head Types
Determining the type of sprinkler head installed is the first step, as the adjustment mechanism differs between models. The two most common types are fixed spray heads and rotor heads. Fixed spray heads are designed for smaller areas, producing a constant, fan-shaped spray pattern with a short throw distance, typically ranging from four to fifteen feet.
Rotor heads are engineered for larger areas and distribute water through rotating streams. Their throw distance is much greater, usually covering a radius between fifteen and seventy feet, depending on the model and water pressure. A fixed spray head maintains a static pattern, while a rotor head turns back and forth or in a full circle during operation. Adjustment tools are simple, usually involving a small flathead screwdriver for fixed heads and either a specialized key or a small flathead for rotors.
Adjusting Fixed Spray Head Distance
Distance adjustment on a fixed spray head is performed by modifying the water stream directly at the nozzle. Use a small flathead screwdriver to manipulate the radius adjustment screw, which is centrally located on the top of the nozzle. This screw acts as a diffuser, interrupting the flow of water as it exits the head.
Turning the screw clockwise drives it further into the water stream, breaking up the flow into finer droplets. This decreases the overall throw distance of the spray pattern. Only small, incremental adjustments should be made before testing the result.
Turning the screw counter-clockwise retracts the diffuser, allowing a less obstructed, cohesive stream of water to exit the nozzle. This action will slightly increase the spray radius, maximizing the distance for that specific nozzle. Fixed spray heads offer limited distance modification, often only allowing for a reduction of up to 25 percent from the maximum rated distance.
Adjusting Rotor Head Distance
Rotor heads provide greater adjustability, but the distance control mechanism is more complex than the fixed spray head. The primary method for fine-tuning the radius is through the radius reduction screw, which is accessible on the top of the head, often near the arrow indicating the nozzle direction. This screw functions similarly to the fixed head’s diffuser, pushing into the path of the water stream to shorten the throw.
To decrease the distance, turn the specialized adjustment key or small flathead screwdriver clockwise, forcing the screw further into the stream. This adjustment typically allows for a reduction of 25 to 35 percent from the nozzle’s maximum potential distance. It is crucial not to back the screw out so far counter-clockwise that it no longer sits in front of the nozzle, as this can cause the nozzle to be ejected by water pressure.
For major changes to the throw distance, the installed nozzle must be replaced with one that has a different flow rate, measured in gallons per minute (GPM), and a corresponding radius rating. This process involves pulling up the riser with a pair of pliers or a dedicated tool to expose the nozzle housing. Installing a smaller GPM nozzle will reduce the flow and distance, while a larger one will increase it, provided the system’s pressure supports the change.
Verifying Coverage and Troubleshooting
Once adjustments have been made, the system must be run to visually verify that the new radius settings deliver uniform water application. The standard for achieving even coverage is “head-to-head coverage,” meaning the spray from one sprinkler head must successfully reach the location of the adjacent sprinkler head. Observing the system while it runs allows for immediate identification of dry spots or areas of overspray.
A common issue that prevents a head from reaching its intended distance is insufficient water pressure. If the pressure is too low, the stream will fall short regardless of the screw adjustment, necessitating a pressure boost or the installation of heads designed for lower pressure. Spray pattern distortion can be caused by debris partially blocking the nozzle opening; clearing obstructions restores the intended trajectory. If the radius adjustment screw no longer affects the spray distance, the internal threading may be stripped, indicating the entire nozzle or head assembly may require replacement.