Graco PRO 3500WB, Manual

Page: 15 / 48

OPERATION
Filter the Fluid
Filter the fluid to remove coarse particles and sediment
which could clog the spray nozzle.
Install the Fluid Nozzle and Air Cap
WARNING
To reduce the risk of serious bodily injury, including
splashing in the eyes or on the skin or electric
shock, always follow the
Pressure Relief Proce-
dure on page 12 before installing, or removing the
fluid nozzle/air cap assembly.
Do not touch the gun nozzle or come within 4 in.
(101.6 mm) of the nozzle during gun operation or
for 30 seconds after operation stops to allow the
voltage to discharge through the voltage control. It
is recommended that the operator hold the gun in
hand or hang it in the gun holster during this 30 se-
cond period. See ACCESSORIES to order the gun
holster.
1. Choose the correct fluid nozzle and air cap combina-
tion for your application. See Manual 307–803 to
select a fluid nozzle and air cap.
2. Be sure the spray gun ES On-Off Lever is OFF
(0). See Fig 11.
3. Install the air cap and fluid nozzle into the gun barrel
as described in
Air Cap/Nozzle/Resistor Stud
Replacement on page 24.
Adjust the Spray Pattern
Follow these steps to establish the correct fluid flow and
air flow. DO NOT turn the ES On-Off lever to ON
(1) yet:
1. Adjust the fluid flow by using the fluid pressure
regulator installed in the fluid line at the pressure
source.
NOTE: If the fluid supply is a pump, the fluid regulator
MUST be installed at the pump outlet, not
remote from the pump.
2. First, complete all the checks under the Operating
Checklist on page 12. Then turn the ES On-Off lever
to ON
(1). When spraying, the ES indicator light
should glow, indicating the electrostatic charge.
3. Use an air pressure regulator to adjust the degree of
atomization. Always use the lowest air pressure pos-
sible for the most efficiency.
4. A
minimum of 2.8 bar (40 psi) air supply is required to
ensure full voltage from the power supply. The gun
may be operated at a lower air pressure/voltage if
required, but may lose some electrostatic wrap.
5. If the flow to the air cap is still excessive after lower-
ing the inlet pressure below 40 psi, the optional
air
cap control valve (see Fig 11) can be installed and
used to limit air to the air cap. See ACCESSORIES.
6. Use the
fan air control valve to change the shape of
the spray pattern. When increasing to a wide, flat pat-
tern, it may be necessary to increase the supply of
fluid to the gun to maintain the same amount of
coverage over a large area.
NOTE: See SPRAY PATTERN TROUBLESHOOTING
CHART on page 18 to correct spray pattern
problems.
CAUTION
ALWAYS hang the gun with its nozzle pointing
down to avoid having solvent run into the gun air
passages. Solvent in the gun air passages can
cause poor atomization and excessive current de-
mands and damage the gun.