Graco 231–034 Instructions And Parts List page 31

Pressure Control Adjustment
7. Turn the pressure–control knob (B) to the mini-
mum setting (fully counterclockwise).Turn on the
sprayer. The pump should not cycle. See Fig.
22.
If the pump does cycle, remove the plug (17)
from the bottom of the pressure control. Insert a
3/8 inch nut driver through the opening, and un-
screw the adjustment nut (T) just until the sprayer
stops operating.
Adjust the overpressurization switch.
8. Trigger the gun and slowly turn the pressure–con-
trol knob clockwise just until the sprayer starts.
Prime the pump and hose.
9. Slowly turn the pressure–control knob to the maxi-
mum setting. Now, observe the gauge and the red
light on the circuit board. Turn the nut (T) slowly
to increase the 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 the pressure. Release
the trigger and lock the gun trigger safety. Repeat
Step 9 to verify the results.
12. Install the cover on the pressure control.
Adjust the maximum working pressure.
13. Turn off the sprayer. Unlock the gun trigger safety.
Trigger the gun into a grounded waste–container
until the pressure is relieved. Lock the gun trigger
safety.
14. Use the 3/8 inch nut driver to turn the pressure
adjustment nut (T) counterclockwise, one full turn.
15. With the pressure–control knob at the minimum
setting, turn on the sprayer.
16. Slowly turn the pressure–control knob (B) clock-
wise to the maximum setting and hold it there. Use
a 3/8 inch nut driver or a socket wrench to slowly
turn the pressure adjustment nut (T) clockwise un-
til the gauge reads EXACTLY 3000 psi (210 bar).
17. Turn the pressure–control knob to the minimum
setting. Release the gun trigger safety. Trigger the
gun into a grounded waste–container until the
pressure is relieved. Lock the gun trigger safety.
Slowly increase the pressure to verify that the
maximum working pressure is set at 3000 psi (210
bar).
CAUTION
T o prevent corrosion in the pump, use mineral spir-
its to flush the water out of the pump, the hose,
and the gun. Follow the flushing procedure on page
15.
18. Install the plug (17) in the bottom of the pressure
control. Remove the gauge and reinstall the plug.
Flush out the water with mineral spirits.
Ç Ç Ç
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B
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P
Q
71
T
17
Fig. 22
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