Hitachi EM 490 - Manual (Page 14)

307-735 14
TROUBLESHOOTING GUIDE
WARNING
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, adjusting or
cleaning the system, and when changing spray tips.
1. Engage the gun safety latch.
2. Turn the ON/OFF switch to OFF.
3. Unplug the power supply cord.
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 and relieve
pressure gradually. Now clear the tip or hose.
Check everything in the chart before disassembling the sprayer.
PROBLEM CAUSE SOLUTION
Electric motor won’t run Power cord or extension cord unplugged,
or damaged, or building circuit breaker or
fuse has tripped Check, reset or replace.
Motor overload switch 1 has opened Unplug power supply cord, relieve pressure, al-
low motor to cool, decrease pressure.
Pressure setting too low Increase pressure.
Pressure control frozen 2 or damaged by
over–pressurization 3
Try to thaw, or replace pressure control.
Electric motor stops while spraying Power cord or extension cord unplugged,
or damaged, or building circuit or fuse is
blown Check, reset or replace.
Motor overload switch 1 has opened Unplug power supply cord, relieve pressure, al-
low motor to cool, decrease pressure.
Pressure setting too low Increase pressure.
Spray tip or filter plugged Remove and clean.
Wrong type extension cord Use maximum 200 ft (61 m), 3 wires, 12 gauge,
grounded extension cord.
Electric motor runs, but low paint
output or no paint output;
or pump is not stroking Piston ball check not seating Service the pump. See page 16.
See the PROBLEM, “Not enough
paint pressure”, on page 15, also Piston packings worn or damaged Replace the piston. See page 16.
Intake valve ball check not seating Service the pump. See page 16.
. Pump is frozen Thaw 2
Filter element installed upside down Install element correctly. See page 12 or manual
307–273.
Pressure control frozen 2 or damaged by
over–pressurization 3
Try to thaw, or replace pressure control.
Drive assembly damaged Replace drive housing. See page 19.
Displacement pump worn or damaged Replace displacement pump. See page 16.
Sprayer is not primed. Prime sprayer. See page 10.
Electric motor labors when starting,
and trips building circuit breaker or
fuse Motor capacitor has failed Replace the capacitor. See page 20.
Circuit board has failed Replace the circuit board. See page 21.