Graco VRM Instructions Manual page 41

Problem
Material imbalance
Erratic pump movement
Pump output low
313873C
Cause
Inadequate flow from pump; cavitation Clean inlet strainer screen
Pump cavitation
Obstructed fluid hose or mixer; fluid
hose ID too small
Worn piston valve or intake valve in
displacement pump
Inadequate feed pump pressure
Solution
Worn pump inlet valve ball/seat or gasket, repair as
necessary
Feed pump pressure is too low, adjust pressure to
within required range
Open, clear; use hose with larger ID
See pump manual for appropriate repair procedure
Check feed pump pressure and adjust to within
required range
Troubleshooting
41