Pressure Control Adjustment - Graco A Series Instructions-Parts List Manual

USE EXTREME CAUTION WHEN PERFORMING THIS ADJUSTMENT PROCEDURE to reduce the risk of a
fluid injection injury or other serious bodily injury which can result from component rupture, electric shock, fire,
explosion, or moving parts.
This procedure sets the sprayer to3000 psi (210 bar)
MAXIMUM WORKING PRESSURE and sets the
overpressurization switch (microswitch) to approxi-
mately 3600 psi (242 bar).
Perform this procedure whenever the pressure con-
trol assembly is removed and reinstalled or replaced,
or a new circuit board is installed.
Improper adjustment can cause the sprayer to over-
pressurize and result in component rupture, fire or ex-
plosion. It may also prevent the sprayer from obtaining
the maximum working pressure, resulting in poor
sprayer performance.
NOTE: The following tools and equipment are required
for this procedure.
3/8 in. nut driver or 3/8 in. socket wrench
1/4 in. open end wrench
7/16 in. open end wrench
Pail of clean water
Mineral spirits
0–5000 psi, oil–filled test gauge, Part No. 102–814
NEW high pressure spray hose, Part No. 214–915
CAUTION
DO NOT use the gauge supplied with this sprayer
to perform this adjustment. The gauge is rated for
3000 psi (210 bar), and will be damaged if the sys-
tem pressure is raised to 3800 psi (266 bar) as re-
quired for this adjustment. Use gauge 102–814 or
the equivalent.
1. Follow the Pressure Relief Procedure Warning on
page 24.
2. Refer to the above list of tools and equipment need-
ed. Remove the standard gauge and install the 5000
psi (350 bar) gauge. Connect the gun to the new test
hose and connect the hose to the sprayer outlet.
3. Remove the pressure control cover.
A
307–958

PRESSURE CONTROL ADJUSTMENT

WARNING
NEVER try to increase the sprayer's maximum work-
ing pressure of 3000 psi (210 bar ) by performing
these adjustments in any other way. Normal operation
of the sprayer at higher pressures may result in com-
ponent rupture, fire or explosion. To perform this ad-
justment, however, the sprayer pressure must be tem-
porarily increased above the normal working pres-
sure.
Use a new 50 ft (15.2 m) spray hose rated for at least
3000 psi (210 bar) MAXIMUM WORKING PRES-
SURE. A used, under–rated hose could develop a
high pressure leak or rupture.
4. Place the pump suction tube in a pail of clean water.
5. Be sure the gun safety latch is engaged.
NOTE: For Steps 6 through 18, refer to Fig 31–1.
6. Plug in the sprayer.
7. Turn the pressure control knob (B) to the minimum
setting (fully counterclockwise), and turn the sprayer
ON. THE DISPLACEMENT PUMP SHOULD NOT
CYCLE
If it does cycle , remove the plug (346) from the
bottom of the pressure control. Insert a 3/8 in. nut
driver through the opening, and unscrew the
pressure adjustment nut (T) just until the sprayer
stops running.
Adjust the Overpressurization Switch
8. With the spray gun triggered, slowly turn the pres-
sure control knob clockwise just until the sprayer
starts. Prime the pump and hose. Release the trig-
ger.
9. Slowly turn the pressure control knob to the maxi-
mum setting. While watching the red light on the cir-
cuit board and the pressure gauge (A), turn the nut
(T) slowly to increase pressure until the red light
goes out and the gauge reads between 3400 –3800
psi (238 – 266 bar).
If the red light does not go out by 3800 psi
(266 bar), loosen the nut (P) and adjust the stud
(Q) until the light goes out.
If the red light goes out before 3400 psi (238
bar), loosen the nut (P) and adjust the stud (Q)
until the light goes out between 3400 – 3800 psi
(238 – 266 bar).
10. Tighten the nut (P) if it was loosened in Step 9.
11. Trigger the gun to relieve pressure. Release the trig-
ger and engage the safety latch. Repeat Step 9 to
verify your results.
12. Install the pressure control cover.