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How to Adjust the Hunter PGP Sprinkler Rotor Head

Hunter PGP rotor heads are widely used in residential and commercial irrigation systems for their reliability and versatility. Over time, even the best sprinkler systems require adjustments for optimal performance. Whether you’re aiming to tweak the spray distance or alter the arc of the water, adjusting your Hunter PGP rotor head is a straightforward process. Here’s how to do it.

Tools You Will Need:

  • Hunter rotor tool or a small flat-head screwdriver
  • Water supply to the sprinkler system


Adjusting the Spray Arc:

The spray arc (or radius) refers to the degrees of coverage that the sprinkler provides, ranging from 40 degrees to a full 360 degrees.

1. Locate the Adjustment Socket:

Find the adjustment socket on top of the Hunter PGP rotor head. It’s typically marked with a “+” and “-” symbol.

2. Insert the Rotor Tool or Screwdriver:

Insert the plastic end of the Hunter rotor tool or the tip of the flat-head screwdriver into the adjustment socket. This will engage the arc adjustment mechanism.

3. Adjust the Arc:

  • To increase the arc, turn the tool clockwise (towards the “+” sign).
  • To decrease the arc, turn the tool counterclockwise (towards the “-” sign).

Note that each full 360° turn of the wrench will change the arc by approximately 90°. Adjust until you’ve achieved the desired arc.

Adjusting the Spray Distance:

The spray distance or radius determines how far the water is thrown from the sprinkler.

1. Locate the Radius Adjustment Screw:

At the top of the sprinkler head, you’ll find a small screw – this is the radius adjustment screw.

2. Adjust the Radius Screw:

  • To reduce the throw distance, turn the screw clockwise to run water over the screw.
  • To increase the distance, turn the screw counterclockwise. Ideally, the throw should not be adjusted beyond the specified maximum for the rotor nozzle installed.

Be cautious when making this adjustment as overtightening the screw can stop the flow of water completely, while completely loosening it can remove the nozzle.

Tuning the Rotor Head Direction (Right Stop Position):

The right stop position is the fixed point where the rotor head stops rotating and changes direction.

1. Rotate the Sprinkler to the Right Stop:

Manually twist the turret to the right to find the fixed stop position.

2. Adjust the Fixed Right Stop Position:

If you need to change the right stop position:

  • Lift the rotor head out of the ground slightly.
  • Twist the entire body of the sprinkler including the casing, not just the turret, to the left or right to realign the right stop with the desired starting point of your watering zone.

Final Steps:

Once your adjustments are complete:

  • Test the sprinkler by running your irrigation system.
  • Fine-Tune as necessary to ensure coverage is even and accurate according to your landscape needs.
  • Replace the soil tightly around the rotor head if you had to lift it out for adjustment.


  • Perform adjustments while the system is off to avoid getting wet.
  • Small adjustments can make a significant impact; turn adjustments slowly and incrementally.
  • Check the manufacturer’s instructions for the specifics regarding maximum and minimum radius and arc adjustments as over-adjusting can damage the rotor.

Adjusting your Hunter PGP rotor head regularly will help maintain an efficient watering system, leading to a healthy and beautiful garden or lawn. Remember to make periodic checks and recalibrate your sprinklers to adapt to changing garden needs and weather conditions.


If you have any questions our irrigation contractors, the experts at SprinklerRepair.com will be glad to help. Give us a call or (888) 427-5022 to set an appointment.