Arc Adjustments
All I-25 Ultra adjustable arc sprinklers are preset at approximately 180˚. Sprinklers
may be adjusted with water on or off. It is recommended that initial adjustment be
made before installation.
1. Using the palm of your hand, rotate the nozzle turret counterclockwise to left stop
to complete any interrupted rotation cycle (Fig. 1).
2. Rotate the nozzle turret clockwise to right stop. This is the fixed side of the arc.
The nozzle turret must be held in this position for all arc adjustments.
To Increase Arc
1. Insert the key end of the Hunter wrench into the adjustment socket
(Fig. 2 & Fig. 3).
2. While holding the nozzle turret at the right stop, turn the wrench clockwise.
Each 360˚ turn of the wrench increases the arc 45˚.
3. Adjust to any arc between 50˚ and 360˚.
4. Wrench will stop turning, or there will be a ratcheting noise, when the maximum arc (360˚) is reached.
5. When set to 360˚, the sprinkler will rotate continually counter-clockwise.
To Decrease Arc
1. Insert the key end of the Hunter wrench into the adjustment socket (Fig. 2 & Fig. 3).
2. While holding the nozzle turret at the right stop, turn the wrench counterclockwise. Each 360˚ turn of the
wrench decreases the arc 45˚.
3. Adjust to any arc between 50˚ and 360˚.
4. Wrench will stop turning, or there will be a ratcheting noise, when the minimum arc (40˚) is reached.
Radius Adjustment
Insert the hex end of the Hunter wrench into the nozzle-retainer/range-
adjustment screw (Fig. 3). Turn the screw clockwise into the stream of water to
decrease the radius, or counterclockwise to increase the radius.
Precipitation Rate Adjustment
Where excessively wet or dry areas are a problem, the precipitation rate may
be adjusted. Simply replace the existing nozzle with a larger one to increase,
or a smaller one to decrease the rate of precipitation.
Nozzle Installation
1. Insert the key end of the Hunter wrench into the lifting socket of a pop-up
sprinkler and rotate wrench 90˚. Pull the riser up to gain access to the
nozzle opening in rotating turret.
2. Using the Hunter wrench, loosen the nozzle-retainer/range-adjustment
screw. If a nozzle is already installed in the sprinkler, it may now be
removed with pliers by grabbing the tab in the center and pulling out.
3. Slip the desired nozzle into the nozzle socket. Note that the socket is
angled up 25˚ (Fig. 4). Make sure that nozzle is fully seated and
does not protrude from housing. Tighten the nozzle retainer/range-
adjustment screw.
Typical Installation
Full Circle Rotation Speed
I-25 Ultra Standard = 3 minutes (approx.)
I-25 Ultra High Speed = 1 minutes (approx.)
Data represent test results in zero wind. Adjust for
local conditions. Radius may be reduced up to 25%
with adjustment screw (this may alter the uniformity
of the spray pattern).
Hunter Industries Incorporated • The Irrigation Innovators
© 2008 Hunter Industries Incorporated
www.HunterIndustries.com
P/N 700594 LIT-471 9/08
Institutional Series™
I-25
Ultra
Gear-Driven Sprinklers
SS
Lift-up Socket
To Service Riser:
screw accessed
thru membrane
here (caution -
under spring
tension)
Specific
Model
Flow Direction Arrow
& Nozzle-Retainer/
Range-Adjustment Screw
Arc Adjustment
Socket
Arc Adjustment Direction
Fig. 3
Fig. 2
Fig. 1
Note: When
installing nozzles,
it is no longer
necessary to
select and install
a matching
stator ring.
Fig. 4
