Troubleshooting Guide - Graco EM 490 Instructions-Parts List Manual

Pressure Relief Procedure
To reduce the risk of serious bodily injury , including
fluid injection, splashing in the eyes or on the skin, or
injury from moving parts, always follow this procedure
when you shut off the sprayer, when checking, adjust-
ing or cleaning the system, and when changing spray
tips.
1 Engage the gun safety latch.
2 Turn the ON/OFF switch OFF.
3 Unplug the power supply cord.
Check everything in the chart before disassembling the sprayer.
PROBLEM
Electric motor won't run
Electric motor stops while spraying Power cord or extension cord unplugged,
Electric motor runs, but low paint
output or no paint output,
OR pump is not stroking
See the PROBLEM, "Not enough
paint pressure", on page 12, also
.
Electric motor labors when starting,
and trips building circuit breaker ,
fuse or motor overload switch

TROUBLESHOOTING GUIDE

WARNING
CAUSE
Power cord or extension cord unplugged,
or damaged, or building circuit breaker or
fuse has tripped.
1
Motor overload switch has opened.
Pressure setting is too low.
Pressure control frozen or damaged by
overpressurization.
or damaged, or building circuit or fuse is
blown.
1
Motor overload switch has opened.
Pressure setting is too low.
Spray tip is plugged.
Wrong type of extension cord.
Piston ball check not seating.
Piston packings are worn or damaged.
Intake valve ball check not seating.
Pump is frozen.
Pressure control frozen or damaged by
3.
overpressurization
Drive assembly damaged.
Displacement pump worn or damaged.
Sprayer is not primed.
Start switch has failed.
Motor capacitor has failed.
Motor is incorrectly wired for voltage being
used.
4 Disengage the gun safety latch. Hold a metal part
of the gun firmly to the side of a grounded metal
pail, and trigger the gun.
5 Engage the gun safety latch.
6 Open the fluid pressure drain valve and leave it
open until you start the sprayer again.
If you suspect the hose or spray tip is completely
clogged or that pressure is not fully relieved after fol -
lowing the steps above, VERY SLOWLY loosen the
tip guard retaining nut or hose end coupling to relieve
pressure gradually. Now clear the tip or hose.
SOLUTION
Check, reset or replace.
Unplug power supply cord, relieve pressure, al-
low motor to cool, decrease pressure.
Increase pressure.
2
Try to thaw , or replace pressure control.
Check, reset or replace.
Unplug the power supply cord, relieve pressure,
allow motor to cool, decrease pressure.
Increase pressure.
Remove and clean.
Use maximum 15 m (50 ft), 3 wires, 2.5 mm (12
gauge) minimum gauge, grounded extension
cord.
Service the pump. See page 19.
Replace the piston. See page 19.
Service the pump. See page 19.
2
Thaw
2
Try to thaw , or replace pressure control.
Replace the drive housing. See page 14.
Replace the displacement pump. See page 19.
Prime the sprayer. See page 6.
Replace the start switch. See page 16.
Replace the capacitor. See page 16.
Verify wiring. See page 5.