Graco EM 490 Instructions-Parts List Manual page 20

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REMOVING and REPLACING PRESSURE CONTROL
and unscrew swivel union
( 8 4 )
from nipple (313).
Hold the nut (H) et the pressure control with a wrench
Remove filter (47). See Fig 19.
Disconnect hose
( 5 2 1
from the nipple (3021. See Fig
20.
Use extreme caution when removing the elbow
(312) or nipple (3131 from the pressure control.
Any twisting or jarring of the pressure control
fit-
ting could alter the factory setting of the control or
permanently damage the control.
IcA
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Remove screw'
(71,
lockwashers (4), and n u w f 3 ) .
Remove pressure control
( 5 0 )
from frame. See Fig 20.
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trol
(50).
See Fig 21.
Remove screws ( 2 5 ) end cover (41) from pressure con-
Disconnect red, pink and brown motor leeds from cir-
from grounding screw (301
I,
and black motor lead from
cuit board ( 8 6 ) . Disconnect green and yellow motor lead
toggle switch (316). See Fig 21.
NOTE:
Circuit board ( 8 6 ) is not included with pressure
control (50) replamment assembly. Order
separately
if new circuit board is needed.
Unscrew nut on end of conduit (1) from connector
conduit while carefully guiding wires through connector
(130). See Fig 21. Pull pressure control
( 5 0 )
away from
(130).
unscrew
it
from pressure control. Slide strain relief up
Loosen knurled part of power cord strain relief
(90).
and
on power cord to provide clearance, and unscrew con-
duit connector (130). See Fig 21.
Remove the screw 1301). conduit connector (130). ter-
minal
(a),
lockwasher (304). power supply cord (305).
and strain relief (306) from the old pressure control.
the new pressure control.
Replace any damaged pans. Assemble these parts to
calibrate the pressure control. See page
22.
Replace in the reverse order of disassembly and then
CAUTION
Failure to observe the following may cause poor
damage to the pressure control:
performance or excessive pressure and permanent
(1) Always use nylon spray hose a t
50 ft (15.2 m)
12) Never use a wire braid spray hose.
(3) Never attach a spray hose to the filter drain
valve.
(4) Never add any type of shut off device between
the pump outlet and the spray gun.
( 5 ) Be sure to check filter for clogging or incorrect
assembly if tip clogging frequency increases.
( 6 ) Never allow flushing water or water base paint
to freeze in the system.
1
minimum length.
Fig 19
I
The pressure control MUST be calibrated
WARNING
whenever a new or used microswitch or pressure
control assembly is removed and reinstalled or
replaced to be sure the control is properly
calibrated. Failure to properly calibrate the
pressure control can cause the sprayer to over-
explosion. It may also prevent the sprayer from
pressurize and result in component rupture, fire or
would result in poor sprayer performance.
obtaining the maximum working pressure which
20
307-735