Graco 333013B Instructions - Parts Manual page 33

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 Fluid Voltage
Discharge and Grounding Procedure, page 22.)
3. Follow the Pressure Relief Procedure on page 22.
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 turbine air to the gun on. Measure the volt-
age at the gun electrode with a voltage probe and
meter.
7. Discharge the system voltage by waiting 30 sec-
onds and then touching the gun electrode with a
grounded rod.
8. Check the meter reading:
• If the meter reading is 45 to 55 kV, the gun and
fluid hose are okay, and the problem is in the
voltage isolation system.
• If the meter reading is below 45 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.
10. Turn the turbine air to the gun on. Measure the volt-
age at the gun electrode with a voltage probe and
meter.
11. If the meter reading is 55-60 kV, the gun power sup-
ply is okay, and there is probably a dielectric break-
333013B
down somewhere in the fluid hose or gun. Continue
with step 12.
If the reading is below 55 kV, do the electrical tests on
page 33 to check the gun and power supply resistance.
If those tests show the gun and power supply are okay,
continue with step 12.
12. A dielectric breakdown is most likely in one of the
following three areas. Repair or replace the compo-
nent 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 PTFE layer. Disconnect
the fluid hose from the gun, and look for
signs of fluid contamination on the outside
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 40), and
look for signs of fluid leakage or any black-
ened 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
seals on the end of the hose. Remove the
hose at the gun connection and look for
signs of fluid leakage along the tube.
13. 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.
14. Reconnect the fluid hose.
15. Check the gun voltage with the voltage probe and
meter before filling the gun with fluid.
Troubleshooting
33