Control Calibration - Graco EM 390 Instructions-Parts List Manual

PRESSURE

CONTROL CALIBRATION

USE EXTREME CAUTION WHEN PERFORMING THIS CALIBRATION PROCEDURE to reduce the risk oi
an injection injury or other serious bodily injury which can result from component rupture, electric shock, fire, ex.
plosion, or moving parts.
This procedure sets the sprayer to
MAXIMUM WORKING PRESSURE.
This procedure must be performed whenever a
microswitch or pressure control assembly is removed
and reinstalled or replaced to be sure the sprayer is
properly calibrated.
Improper calibration can cause the sprayer to over-
pressurize and result in component rupture, fire or
explosion. I t may also prevent the sprayer from ob-
taining the maximum working pressure which would
result in poor sprayer performance.
Tools
Needed:
(15.2
NEW 50 ft
210-541
hose, Part No.
Needle Valve. Part No. 102-715
open e i d wrench
Fluid-Filled Pressure Gauae. Part No.
Mineral Spirits (for flushing after test)
1. Follow the Pressure Relief Procedure Warning
14.
on page Install the new
hose to the sprayer outlet. On the other end of the
hose install the needle valve. Install the fluid-filled
pressure gauge in the top port of the fluid filter.
2.
Open the needle valve slightly. Turn the pressure
control knob (D) to the minimum setting. 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.,
3. 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
close it all
the way. Observe the Dressure a t which
the pump stalls, 'which should
(172 bar).
NOTE: The slower the pressure is brought up, the
easier is to note the exact
it
Closing the needle valve quickly causes the
pressure to rise too fast which gives a false
reading.
relieve pressure. Use a
turn the pressure adjustment nut, at the bottom of
the pressure control knob shaft
wise turn or less, then repeat steps
relieve pressure. Turn the pressure adjustment nut
turn or less and repeat steps
clockwise
Repeat until the proper stall pressure is obtained.
307-724
25)
(See Fig
1172
psi bar)
(210
psi bar) airless spray
or
(15.2
50 ft
be
approximately
stall pressure.
open end wrench to
counterclock-
2 3.
and
2 3.
and
NEVER attempt to increase the fluid outlet pressure
by performing these calibrations in any other way.
NEVER EXCEED psi
WORKING PRESSURE, Normal operation of the
sprayer at higher pressures could result in compo-
50
ALWAYS use a new
rated for 3OOO psi 1210 bar) MAXIMUM WORKING
PRESSURE when performing this procedure. A
used, underrated hose could develop a high pressure
leak or rupture.
AVOID touching the wire in the pressure control
assembly when the control box cover is removed to
reduce the risk of electric shock,
4. Now check to see at whet pressure the sprayer
turn it on, close the needle valve, and set the
at
pressure maximum. Allow the sprayer to run until
it stalls.
5. Now open the needle valve very slowly while ob-
serving the pressure gauge. Check to see if the
pressure drops to approximately
before starting again.
sprayer, but do not relieve pressure. Turn the dif-
ferential wheel (F) counterclockwise just one notch
4 and 5. Check the pressure drop
end repeat Steps
again, and repeat if necessary.
NOTE:
If you adjust the differential wheel, recheck
the stall pressure (steps
the stall pressure has not changed.
6.
Follow the Pressure Relief Procedure Wernlng
14,
on page flush the water out with mineral spirits,
relieve pressure again, then remove the test hose,
needle valve and pressure gauge.
Fig 25
(172 bar) MAXIMUM
(15.2
foot
2100 psi (147 bar)
2 and to be sure
. .
... , .
..
. .
.
,
. .
....
. .
.,.
, . .
.
. : .
:
. . . ..
. .
.
. .
.
,