System Verification
3A0420H
29
System Verification
Graco recommends running the following tests daily.
Check for Normal Operation
Every time you start spraying:
•
Watch the fluid gauges (AF). A pressure drop
occurs during pump stroke changeover. It should be
quick and synchronous.
•
Stop the pumps on the upstroke. Check that both
gauges hold pressure for at least 20 seconds. See
Pump Troubleshooting
on page 32.
NOTE: If one gauge drops, the others will rise.
•
Stop the pumps on the downstroke. Check that all
gauges hold pressure.
•
If using feed pumps, check that both feed pumps run
during the proportioner upstroke.
Mix and Integration Tests
Use the following tests to check for proper mix and inte-
gration.
Butterfly Test
At low pressure, and with the spray tip reversed, dis-
pense a 1/2 in. (12.7 mm) bead of material onto foil until
multiple changeovers of each pump have occurred. Fold
the sheet of foil over the fluid then peel it back and look
for unmixed material (appears marble-like), or color
changes.
Curing Test
Spray a single continuous pattern on foil at typical pres-
sure setting, flow rate, and tip size until multiple change-
overs of each pump have occurred. Trigger and
de-trigger at typical intervals for the application. Do not
overlap or cross over your spray pattern.
Check curing at various time intervals, listed on the
material data sheet. For example, check for dry to touch
by running your finger along the test pattern’s entire
length at the time listed on the data sheet.
NOTE: Spots that take longer to cure indicate insuf-
ficient pump loading, leakage, or lead/lag errors at a
remote mix manifold.
Appearance Test
Spray material onto a metal substrate. Look for varia-
tions in color, gloss, or texture that may indicate improp-
erly catalyzed material.
Monitor Fluid Supply
An empty pump will quickly accelerate to a high speed,
and may damage itself and the other displacement
pump because it causes a pressure rise in the other
pump. If a supply container runs dry, stop the pump
immediately, refill the container, and prime the system.
Be sure to eliminate all air from the system.
Check Pot Life
Check the fluid manufacturer's instructions for fluid pot
life at your fluid temperature. Flush mixed fluid out of the
mix manifold, hose, and gun before pot life time expires,
or before a rise in viscosity affects the spray pattern.
Ratio Check
Check the ratio at the mix manifold after any changes to
the proportioning system. Use Ratio Check Kit 24F375
to check the ratio at the mix manifold. See manual ratio
check kit manual for instructions and parts.
NOTE: To prevent an inaccurate ratio check when
feed pumps are used in your system, the feed pres-
sure cannot be more than a maximum of 25% of the
proportioner outlet pressure. High feed pressure
can float the proportioner pump check balls, result-
ing in an inaccurate ratio check. There must be back
pressure on both sides of the mix manifold when
checking the ratio.
NOTICE
To prevent pumping air into the system and cause
incorrect proportioning, never allow the feed pump or
solvent pump containers to run dry.
