Graco A Series Instructions-Parts List Manual page 10

IV. Set the fluid and air pressure
1. With the system primed and the gun regulator
closed, trigger the gun and adjust the pump air
pressure regulator (5a) to 60 psi (420 kPa, 4.2
bar).
2. With the air cap removed, trigger the gun into a
grounded metal waste pail and set the fluid pres-
sure regulator (6). Use the fluid pressure setting
provided by your fluid supplier, if available. Other-
wise use the following instructions to determine the
fluid pressure.
To determine the fluid pressure setting, hold the
gun parallel to the floor. (Be sure to catch the fluid
in a container). With the gun air pressure turned
OFF, trigger the gun. Adjust the fluid pressure
regulator (6) until the straight fluid stream is within
the range indicated for the viscosity of your fluid
before it drop off. See Fig. 10. Make note of this
pressure on the fluid gauge; it is your optimal fluid
pressure setting.
3. Release the gun trigger. Install the air cap.
Fluid Viscosity
Measured with #2 Zahn cup
Light (18–25 seconds)
Medium (25–40 seconds)
Heavy (40–60 seconds)
Fluid droop:
straight
stream
before fluid
drops off
Fig. 10
Operation
Fluid Droop
8–10" (200–250 mm)
6–8" (150–200 mm)
4–6" (100–150 mm)
4. Partially trigger the gun so only air is emitted. Set
the gun air regulator (5b) pressure to 70 psi (490
kPa, 4.9 bar).
5. Spray a stationary test pattern on scrap paper.
Hold the gun 10–12 in. (250–300 mm) from the
paper and spray for 2 or 3 seconds. If the spray
pattern is poorly atomized, the air and / or fluid
pressures may need adjustment.
If the spray pattern atomization is not fine enough,
increase the gun air pressure. If the spray pattern
atomization is too fine, decrease the gun air pres-
sure. If the air atomization is still not good enough,
try lowering the fluid pressure in increments of 2 or
3 psi to achieve the desired finish quality.
NOTE: For the most efficient paint usage, use the
lowest air pressure needed to obtain a good finish.
Higher air pressures create more overspray and use
more fluid.
KEY
A ES indicator light
B ES On–Off lever
I is ON and 0 is OFF
C Fan control valve
Fig. 11
6. Turn the ES On/Off lever (B) to ON (I position).
See Fig. 11.
NOTE: When spraying, the ES indicator light (A) will
glow, indicating the electrostatic charge. See Fig. 11.
A
E
I O
S
B
C