Hitachi EM 490 - Manual (Page 22)

307-735 22
PRESSURE CONTROL ADJUSTMENT
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 to 2750 psi (190 bar)
MAXIMUM WORKING PRESSURE.
Perform this procedure whenever the microswitch or
pressure control assembly is reinstalled or replaced,
to be sure the sprayer is properly calibrated.
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.
NEVER attempt to increase the fluid outlet pressure
by performing these adjustments in any other way.
Normal operation of the sprayer at higher pressures
could result in component rupture, fire or explosion. To
perform this adjustment, however, the sprayer pres-
sure must be
temporarily increased above the normal
working pressure.
Use a new 50 foot (15.2 m) spray hose, rated for at
least 3000 PSI (210 BAR) MAXIMUM WORKING
PRESSURE, when performing this procedure. A
used, under–rated hose could develop a high pres-
sure leak or rupture.
WARNING
Service Tools Needed:
D NEW 50 foot (15.2 m), 3000 psi (231 bar). flexible ny-
lon, airless spray hose, Part No. 223–541
D
0–5000 psi (0–350 bar) fluid–filled pressure gauge,
Part No. 102–814
D
Needle valve, Part No. 102–715 or 103–067
D
3/8 in. socket wrench
D 5 gallon pail and water
D Mineral spirits
1. Follow the Pressure Relief Procedure Warning on
page 14.
2. Connect the new 50 ft (15.2 m) spray hose to the
sprayer outlet. Install the needle valve on the other
end of the hose. Install the fluid–filled pressure gauge
in the top port of the fluid filter.
3. Remove the pressure control cover (41) and the plug
(135) (
see the parts drawings) from the bottom of the
pressure control. In Step 6, you will insert the 3/8 in.
socket wrench through the plug hole (C) to engage
the pressure adjustment nut (B) which is located on
the bottom of the pressure control knob shaft.