Hitachi 220-856 Paint Sprayer User Manual


 
22 307-830
Pressure
Control Adjustment
Fig.
22
A
B
D
TIGHTEN
C
0750
68
E
+
NOTE:
Refer to Fig. 22 for the remainder of this
procedure.
2.
Remove the plug (68).
3.
Open the needle valve slightly
. T
urn the pressure
adjusting knob (A) to the minimum setting.
4.
Plug in the sprayer and turn the switch (E) ON.
Increase the pressure just enough to start the
sprayer
. Fully prime the hose, being sure to elimi
-
nate all air from the system.
5.
Open the needle valve a just enough to allow the
pump to run continuously
, and turn the pressure
adjusting knob to maximum. V
ery slowly start to
close the needle valve. Observe the pressure at
which the pump stalls, which should be approxi
-
mately 2750 psi (190 bar).
6.
If the pressure is lower than 2750
psi
(190
bar):
Unplug the sprayer and relieve pressure. Insert the
wrench through the hole (C) and tighten the adjust
-
ment nut (B)
1/8 turn or less. Repeat steps 5 and
6.
If the pressure is higher than 2750
psi
(190
bar):
Unplug the sprayer and relieve pressure. Insert the
wrench through the hole (C) and loosen the pres
-
sure adjustment nut (B) 1/8 turn or less. Repeat
steps 5 and 6. Repeat this procedure 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 spray
-
er
, turn it on, close the needle valve, and set the
pressure at maximum. Allow the sprayer to run
until it stalls.
NOTE:
In Step 8, 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.
8.
Open the needle valve very slowly while observing
the pressure gauge. Check to see if the pressure
drops to approximately 2350 psi (161 bar) before
the sprayer starts again.
9.
If the pressure is not
approximately 2350 psi
(161
bar
): Shut of
f 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 it has
not changed.
10.
Relieve pressure. Flush the water out with mineral
spirits. Relieve pressure. Install the plug (68).
Remove the test equipment.