Graco 223-599 Instructions Manual page 23

D
C
Fig 22
4. Open the needle valve slightly. Turn the pressure con-
trol knob (A) to the minimum setting.
5. Plug in the sprayer and turn the switch ON. Increase
the pressure setting just enough to start the sprayer.
Prime the hose, being sure to eliminate all air from the
system.
6. Open the needle valve a little more––enough to allow
the pump to run continuously––and turn the pressure
control knob to maximum. Now , very slowly start to
close the needle valve, but don't close it all the way.
Observe the pressure at which the pump stalls, which
should be approximately 2750 psi (190 bar).
NOTE: The slower the pressure is raised, the easier it is
to note the exact stall pressure. Closing the
needle valve quickly causes the pressure to rise
too fast which gives a false reading.
PRESSURE CONTROL ADJUSTMENT
ON/OFF SWITCH
A
B
TIGHTEN
If the pressure is lower than 2750 psi (190 bar):
Unplug the sprayer . Relieve pressure. Insert the
wrench and untighten the pressure adjustment nut
1/8 turn or less, then repeat steps 5 and 6.
If the pressure is higher than 2750 psi (190 bar):
Unplug the sprayer . Relieve pressure. Insert the
wrench and tighten the pressure adjustment nut 1/8
turn or less and repeat steps 5 and 6. Repeat this pro-
cedure until the proper stall pressure is obtained.
7. Now check to see at what pressure the sprayer starts
to run again after it stalls. Plug in the sprayer, turn it
on, close the needle valve, and set the pressure at
maximum. Allow the sprayer to run until it stalls.
8. Open the needle valve very slowly while observing
the pressure gauge. Check to see if the pressure
drops to approximately 2350 psi (164 bar) before
starting again.
If the pressure is not 2350 psi (164 bar):
Shut off and unplug the sprayer , but do not relieve
pressure. T urn the dif ferential wheel (D) just one
notch and repeat Steps 5 and 6. Check the pressure
drop again, and repeat if necessary.
NOTE: If you adjust the dif ferential wheel, recheck the
stall pressure (steps 5 and 6) to be sure the stall
pressure has not changed.
9. Follow the Pressure Relief Procedure Warning on
page 14. Flush the water out with mineral spirits. Re-
lieve pressure again. Install the plug (135) and the
pressure control cover (41). Remove the test hose,
needle valve and pressure gauge.