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Institutional Series

I-20

Gear-Driven Sprinklers

ARC ADJUSTMENT
The I-20 pop-up sprinkler should be 

installed at finished grade as shown in the 

illustration (Fig. 1).

Arc Adjustments:
Adjustable heads are preset to 

approximately 180°. Sprinklers may be adjusted with water on or off. It is 

recommended that initial adjustments be made before installation.
1.    Using the palm of your hand, rotate the 

nozzle turret counterclockwise to the left stop 

to complete any interrupted rotation cycle 

(Fig. 2).

2.    Rotate the nozzle turret clockwise to the 

right stop. This is the fixed side of the arc. 

The nozzle turret must be held in this 

position for arc adjustments. The right stop 

does not change.

To Increase the Arc:
1.    Insert the plastic key end of the Hunter 

wrench into the adjustment socket   

(Fig. 3 & 4).

2.    While holding the nozzle turret at the right 

stop, turn the wrench clockwise. Each full 

360° turn of the wrench will increase the   

arc 90°.

3.    Adjust to any arc between 50° and 360° 

 

(Fig. 5).

4.    The wrench will stop turning, or there will be a ratcheting noise, when the 

maximum arc of 360° (full-circle) has been reached.

5.  When set to 360°, the sprinkler will rotate continually counter-clockwise.
 To Decrease the Arc:
1.  Insert the plastic key end of the Hunter wrench into the adjustment socket 

(Fig. 3 & 4).

2.    While holding the nozzle turret at the right stop, turn the wrench counter -

clockwise. Each full 360° turn of the wrench will decrease the arc 90°.

3.    Adjust to any arc between 50° and 360° (Fig. 5).
4.    The wrench will stop turning, or there will be a ratcheting noise, when the 

minimum arc of 50° has been reached. 

Fig. 1

Fig. 2

Note:

 It is not necessary to disassemble the sprinkler to make adjustments.

Fig. 5

Minimum

Arc

50

°

360

°

Maximum

Arc

Fig. 4

Decrease Arc

Increase Arc

Insert the steel hex end of the Hunter wrench into 

the radius adjustment screw (Fig. 6). Turn the screw 

clockwise (into the stream of water) to decrease the 

radius, or counterclockwise to increase the radius. 

Radius can be reduced up to 25%. 

Fig. 6

RADIUS / DISTANCE OF THROW

Caution: Turning the adjustment 

screw clockwise more than five 

full turns may result in a lost radius 

adjustment screw.

R EC L AIMED  ID
All Hunter rotors are available with 

a purple rubber cover permanently 

attached. The purple cover shows 

that reclaimed water is being used 

for the project, which promotes safety on the job site.

S HRU B  STA K ING K IT  P/ N 463551
The kit is designed for PGP-00 and I-20-00. It allows you 

to safely attach a shrub sprinkler to a piece of 

5

16

"

 rebar. 

The kit comes with a heavy-duty locking tie to attach the 

sprinkler to the kit.

NOZZ L E INSTA LL ATION
1.    Insert the plastic key end of the Hunter wrench into 

the lifting socket of the sprinkler and turn 90°. Pull the 

riser up to gain access to the nozzle socket (Fig. 8).

2.    Using the hex key of the 

Hunter wrench, turn the radius 

adjustment screw (Fig. 6) 

counterclockwise to be sure 

it is not blocking the nozzle 

socket opening. If a nozzle 

is already installed, it can 

be removed by backing out the 

adjustment screw and turning on the 

water, or by pulling outward on the 

nozzle removal post with a pair of 

needle-nosed pliers.

3.    Slip the desired nozzle into the 

nozzle socket (Fig. 7). Note that the 

socket is angled up 25°. Then tighten 

the nozzle range screw. The triangle 

on the rubber cover will always 

indicate the location of the nozzle 

and direction of water flow when the 

sprinkler is retracted. 

AL IG NIN G  THE RI G HT (FIXED) SIDE OF ARC
If the right side of the arc is not properly aligned, the 

results may be a wet walkway or a dry turf area. The right 

side arc can easily be realigned. One way to realign the 

right stop is to turn the whole sprinkler body assembly 

and the fitting below it, left or right to the desired position. 

This may require temporary removal of the soil around 

the sprinkler to allow you to grip the sprinkler housing.
Another way to reset the right arc is to unscrew the body 

cap counterclockwise and remove the internal assembly 

from the body. Once removed, rotate the nozzle turret 

to the right stop, screw the internal assembly back into 

the body with the nozzle aligned to the right side of the 

area you want irrigated (Fig. 9). At this point you have 

realigned the right arc stop, and you can adjust the left 

arc to an appropriate setting.

Note: 

It is not necessary to dig up and remove the whole 

sprinkler to realign the right arc.

TURNIN G  F LOW ON OR OFF
Insert the plastic key end of the Hunter 

wrench into the FloStop

®

 adjustment 

socket (Fig. 3 & 10). Turn wrench 

clockwise to decrease or shut off the 

flow. Turn the wrench 

counterclockwise to 

increase the flow.

Fig. 7

Nozzle Removal

Post

Fig. 10

Fig. 9

Model

Nozzle

No.

Pressure

in PSI

Degrees of

Trajectory

Max Height

of Spray (ft.)

Distance from head (ft.)

to Maximum Height

I-20

1.5

45

25

8'

23'

Blue

2.0

45

25

8'

23'

2.5

45

25

9'

26'

3.0

45

25

10'

28'

4.0

45

25

11'

30'

5.0

45

25

11'

30'

6.0

55

25

12'

32'

8.0

55

25

13'

32'

I-20  

Low Angle

2.0

50

13

5'

22'

2.5

50

13

4'

22'

3.5

50

13

4'

22'

4.5

50

13

4'

22'

I-20  

18' Short 

Radius

.50

50

15

5'

8'

1.0

50

14

6'

9'

2.0

50

3

1'

6'

I-20

25' Short 

Radius

.75

50

22

7'

13'

1.5

50

18

7'

13'

3.0

50

8

1'

6'

Plastic  Ke y End

Steel He x End

NON -STRI PP ABL E  B AC K DRI VE
This I-20 sprinkler is designed with an internal device that prevents damage to 

the internal gear drive if it should be turned by vandals. This important feature 

works when the nozzle turret is turning in either direction. This makes the 

sprinkler very durable in all applications.

AUTO  ARC  RETURN
This I-20 sprinkler is designed with an 

internal device that re-aligns the arc if it is 

turned by vandals. This important feature 

works when the nozzle turret is turning in 

either direction. When forced outside of the 

originally set arc, the sprinkler takes the 

shortest path back to the pattern without 

going completely around. This saves 

the non-irrigated areas from getting wet! 

Always a good thing!

    a

uto

-retu

rn

     

if fo

rced

               d

esire

d se

t a

rc

Fig. 3

A

R

C

ADS

O

F

F

I-20

Lifting

Socket

Nozzle

Locator/Radius

Adjustment

Screw

Model

Identification

Arc

Adjustment

FloStop

®

Fig. 8

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