Graco WB3000 Instructions - Parts Manual page 42

Troubleshooting
Tests
If you still have no voltage, separate the spray gun
and hose from the voltage isolation system and
check whether the gun and hose alone will hold
voltage with the following test.
1. Flush the system with water and leave the lines
filled with water.
2. Discharge the system voltage (see
Discharge and Grounding Procedure, page
3. Follow the Pressure Relief Procedure, page
4. Disconnect the fluid hose from the voltage
isolation system.
Avoid allowing any water to leak out of the fluid
hose as that could cause a significant air gap in
the fluid column up to the gun electrode, which
can break the conductivity path and conceal a
potential failure area.
5. Position the end of the hose as far as possible
away from any grounded surface. The end of
the hose must be at least 1 ft. (0.3 m) from any
ground. Make sure that no one is within 3 ft. (0.9
m) of the end of the hose.
6. Turn the ES ON/OFF valve to ON and trigger
the gun just enough to turn on the air to the gun
but not the fluid. Measure the voltage at the gun
electrode with a voltage probe and meter.
7. Discharge the system voltage by waiting 30
seconds and then touching the gun electrode
with a grounded rod.
8. Check the meter reading:
• If the meter reading is 40 to 50 kV, the gun and
fluid hose are okay, and the problem is in the
voltage isolation system.
• If the meter reading is below 40 kV, the
problem is in the gun or fluid hose.
9. Flush the fluid hose and gun with enough air to
dry out the fluid passages.
42
Fluid Voltage
25).
26.
10. Turn the ES ON/OFF valve to ON and trigger the
gun. Measure the voltage at the gun electrode
with a voltage probe and meter.
• If the meter reading is 40-50 kV, the gun
power supply is okay, and there is probably a
dielectric breakdown somewhere in the fluid
hose or gun. Continue with step 11.
• If the meter reading is below 40 kV, do
the Electrical Tests, page
and power supply resistance. If those tests
show the gun and power supply are okay,
continue with step 11.
11. A dielectric breakdown is most likely in one of
the following three areas. Repair or replace the
component that is failing.
a. Fluid hose:
• Check for leakage or any bulges in the
outer cover, which may indicate a pin-hole
leak through the inner layer. Disconnect
the fluid hose from the gun, and look for
signs of fluid contamination on the outside
of the inner portion of the fluid tube.
• Inspect the end of the hose connected to
the voltage isolation system. Look for cuts
or nicks.
b. Fluid needle:
Remove the fluid needle from the gun
(see Fluid Needle Replacement, page
and look for signs of fluid leakage or any
blackened areas, which would indicate arcing
is occurring along the packing rod.
c. Fluid hose connection to the spray gun:
A breakdown at the fluid hose connection
joint would be caused by fluid leaking past
the hose fittings. Remove the hose at the
gun connection and look for signs of fluid
leakage.
12. Before reassembling the gun, clean and dry the
gun fluid inlet tube. Repack the inner spacer of
the fluid packing rod with dielectric grease and
reassemble the gun.
13. Reconnect the fluid hose.
14. Check the gun voltage with the voltage probe
and meter before filling the gun with fluid.
36, to check the gun
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3A2497C