System Verification
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 34.
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
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
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 foil. Look for variations in color, gloss, or texture that may indicate improperly catalyzed material.
Monitor Fluid Supply
NOTICE
To prevent pumping air into the system, which causes incorrect proportioning, never allow the feed pump or solvent pump containers to run dry.
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.
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