20
308–030
PRESSURE CONTROL ADJUSTMENT
1. Relieve pressure. See page 14.
2. Remove the old spray hose. Install the new
hardware and hose as shown in Fig 17. On
the other end of the hose install the needle
valve.
NOTE: Refer to Fig 18 for the remainder of this
procedure.
Fig 18
ON/OFF SWITCH
A
B
C
3. Open the needle valve slightly. Turn the
pressure adjusting knob (A) to the minimum
setting.
4. Plug in the sprayer and turn the switch ON.
Increase the pressure just enough to start the
sprayer. Fully prime the hose.
NOTE: In Step 5, 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.
5. Open the needle valve a just enough to allow
the pump to run continuously, and turn the
pressure adjusting knob to maximum. Very
slowly start to close the needle valve. Observe
the pressure at which the pump stalls, which
should be approximately 2500 psi (190 bar).
If the pressure is lower than 2500 psi (172
bar):
Unplug the sprayer and relieve pressure. Turn
the adjustment nut (B) counterclockwise 1/8
turn or less. Repeat steps 4 and 5.
If the pressure is higher than 2500 psi (172
bar): Unplug the sprayer and relieve pressure.
Turn the adjustment nut (B) clockwise 1/8
turn or less. Repeat steps 4 and 5.
Repeat this procedure until the proper stall
pressure is obtained.
6. Plug in the sprayer, turn it on, close the needle
valve, and set the pressure at maximum. Al-
low the sprayer to run until it stalls.
7. Open the needle valve very slowly while ob-
serving the pressure gauge. Check to see if
the pressure drops to approximately 2100 psi
(147 bar) before starting again.
If the pressure is lower than 2100 psi (147
bar):
Shut off and unplug the sprayer, but do not
relieve pressure. Turn the differential wheel
(C) counterclockwise just one notch and re-
peat Steps 4 and 5. Check the pressure drop
again, and repeat if necessary.
NOTE: If you adjust the differential wheel, re-
check the stall pressure (steps 4 and 5) to
be sure the it has not changed.
8. Relieve pressure. Flush the water out with
mineral spirits. Relieve pressure. Remove the
test equipment.
Summary of Contents for PRO 301
Page 29: ...29 308 030 NOTES...
Page 30: ...30 308 030 NOTES...
