Graco Inc. UNICARB Pro AA4500 - Manual (Page 25)

308936 25
Electrical Tests
The performance and safety of the spray gun are
directly affected by the condition of the electrical
components contained inside the gun. The electrical
tests below can be used to determine the condition of
the power supply (18) and the barrel resistor cartridge
as well as the continuity of the electrical path between
the components.
CAUTION
The barrel resistor cartridge is part of the barrel and
is not replaceable. To avoid destroying the gun
barrel, do not attempt to remove the barrel resistor
cartridge.
Use megohmmeter P/N 218979 (A) and an applied
voltage of 500 volts to complete these electrical tests.
Connect the leads as shown.
WARNING
FIRE, EXPLOSION, AND
ELECTRIC SHOCK HAZARD
Megohmmeter P/N 218979 (A-see Fig.
4) is not approved for use in a hazard-
ous area. To reduce the risk of sparking,
do not use the megohmmeter to do the
electrical tests unless:
D The gun has been removed from the
hazardous area;
D Or all spraying devices in the hazardous area
are turned off, ventilation fans in the hazardous
area are operating, and there are no flammable
vapors in the area (such as open solvent con-
tainers or fumes from spraying).
Failure to follow this warning could cause fire,
explosion, electric shock and result in serious injury
and property damage.
Test Gun Resistance (See Fig. 4)
NOTE: The fluid passage must be flushed and dried to
get an accurate reading.
Measure the resistance between the end of the elec-
trode (1a) and the air fitting (17). The resistance
should be between 329 to 401 megohms. If the resis-
tance is outside the specified range, go to the next
test. If the resistance is correct, refer to Electrical
Troubleshooting on page 24 for other possible
causes of poor performance.
Fig. 4
1a
17
01949
A