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Troubleshooting
334606C 31
PROBLEM CAUSE SOLUTION
Displacement pump operates,
but output is low on upstroke
Piston ball check not seating
properly
Service piston ball check. See
manual 334654
Piston packings worn or
damaged
Replace packings. See manual
334654
Displacement pump operates
but output is low on downstroke
and/or on both strokes
Piston packings worn or
damaged
Tighten packing nut or replace
packings. See manual 334654
Intake valve ball check not
seating properly
Service intake valve ball check.
See manual 334654
Displacement pump air leak
Paint leaks and runs over side of
wet-cup
Loose wet-cup
Tighten wet-cup enough to stop
leakage.
Throat packings worn or
damaged
Replace packings. See manual
334654
Excessive leakage around
hydraulic motor piston rod wiper
Piston rod seal worn or
damaged
Replace these parts. See
Repair manual.
Fluid delivery is low Pressure setting too low Increase pressure, see
Operation manual.
Displacement pump outlet filter
(if used) is dirty or clogged
Clean filter.
Hydraulic motor is worn or
damaged
Bring sprayer to Graco
distributor for repair.
Large pressure drop in fluid
hose
Use larger diameter or shorter
hose.
Sprayer overheats Paint build up on hydraulic
components
Clean hydraulic components.
Oil level is low Fill with oil. See Operation
manual.
Inlet to hydraulic pump
pulley/cooling fan is obstructed
Remove obstructions.
Inlet to 3 phase electric motor
cooling fan is obstructed.
Remove obstructions.
Spitting from gun Air in fluid pump or hose Check for loose connections on
siphon assembly, tighten, then
reprime pump.
Fluid supply is low or empty Refill supply container.
Excessive hydraulic pump noise Low hydraulic fluid level Turn sprayer OFF. Add fluid*.
Air in hydraulic lines Bleed lines. See Repair manual.
*Check hydraulic fluid level often. Do no allow it to become too low. Use only Graco approved hydraulic fluid, page 18.