Graco Delta Spray 308741N Instructions Manual page 11

6. Adjust the Spray Pattern (continued)
NOTE:
D If the fluid adjustment knob is turned in all the way
the gun will emit only air.
D For continuous spraying, turn the fluid adjustment
knob (8) counterclockwise until no restriction of the
trigger movement is felt. When the knob is turned
out far enough, the trigger should be able to touch
the gun handle when the gun is triggered. For the
typical fluid adjustment knob setting, turn the knob
out 1/2 turn more. This setting provides maximum
fluid flow and prevents premature wear on the fluid
nozzle.
E. Open the pattern adjustment valve (25) by turning
the knob fully counterclockwise to achieve a full
fan pattern.
25
Close
(narrower
pattern)
Fig. 12
F. Using the air pressure regulator (F), set the air
supply pressure at about 50 psi (345 kPa, 3.4 bar).
See the Pressure Drop Chart for regulator setting
versus gun inlet pressure comparison.
If available, use the fluid manufacturer's recom-
mendations to set the air line pressure for a high
volume, low pressure, spray gun application.
NOTE: Local laws may limit the maximum pres-
sure to 10 psi (70 kPa, 0.7 bar) at the air cap for
HVLP compliance. The accessory Air Cap Verifica-
tion Kit is available to measure the atomizing pres-
sure at the air cap.
Setup
Fig. 13
Pressure Drop Chart
5/16 inch (7.9 mm) I.D. hose
Recommended hose size to minimize excessive
pressure drop. Expected pressure drops measured
using 25 ft. (7.625 m) long hose, with gun triggered.
Air Regulator Pressure
Setting
psi (kPa, bar)
18.5 (128, 1.3)
34.0 (238, 2.3)
48.0 (335, 3.3)
62.5 (427, 4.3)
Open
76.5 (525, 5.3)
(wider
pattern)
90.5 (624, 6.3)
G. Test the spray pattern and atomization while hold-
ing the gun about 6 to 8 inches (150 to 200 mm)
from the test piece.
7040A
H. If the spray pattern is too wide with the pattern
adjustment knob (13a) turned fully counterclock-
wise, turn the pattern adjustment knob clockwise
until you have the desired pattern size.
NOTE:
clockwise will produce a round pattern.
I. Check the atomization quality again. Increase the
gun air supply pressure with the air pressure regu-
lator in 5 psi (34 kPa, 0.3 bar) increments until you
obtain the desired atomization.
J. If after increasing the gun air supply pressure the
atomization is still unacceptable, try installing a
larger fluid nozzle size to reduce the fluid velocity.
Refer to Fig. 10. Repeat steps 6-E to 6-I until you
obtain the desired atomization.
F
Gun Inlet Pressure
psi (kPa, bar)
10 (70, 0.7)
20 (140, 1.4)
30 (210, 2.1)
40 (280, 2.8)
50 (345, 3.4)
60 (410, 4.1)
urning the pattern adjustment knob fully
T
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308741 11