User's Manual

Troubleshooting
40 3A2593B Repair
Displacement pump operates, but
output is low on upstroke
Piston ball is not seating. Service piston ball. See manual 309277.
Piston packings are worn or damaged. Replace packings. See manual 309277.
Displacement pump operates but output
is low on downstroke and/or on both
sides
Suction tube strainer is clogged. Clean strainer.
Suction tube air leak. Tighten suction tube.
Pressure setting is too low. Increase pressure. See operation manual.
Fluid filter or tip is clogged or dirty.
Clean filter and tip. See operation manual or gun
manual 311254.
Engine speed is too low. Increase throttle setting. See operation manual.
Intake valve ball is packed with material or is
not seating properly.
Clean intake valve. See manual 309277.
Pump packings are worn or damaged. Replace pump packings. See manual 309277.
Large pressure drop in hose with heavy
materials.
Use larger diameter hose and/or reduce overall length
of hose. Use of more than 100 ft x 1/4 in. hose signifi-
cantly reduces performance of sprayer. Use 3/8 in.
hose for optimum performance.
Oil reservoir hydraulic filter is dirty or clogged. Change hydraulic filter and hydraulic oil.
Intake line to pump inlet is not tight. Tighten intake line to pump inlet.
Hydraulic motor is worn or damaged. Bring sprayer to Graco distributor for repair.
Pump is difficult to prime
Suction tube strainer is clogged. Clean strainer
Suction tube air leak. Tighten suction tube
Drain line to paint hopper is clogged. Clean drain line
Intake valve is leaking.
Clean intake valve. Be sure ball seat is not nicked or
worn and that ball seats well. Reassemble valve.
Pump packings are worn. Replace pump packings. See manual 309277.
Paint is too thick. Thin the paint according to supplier recommendations.
Engine speed is too high.
Decrease throttle setting before priming pump. See
operation manual.
Low stall or run pressure shown on
display
New pump or new packings
Pump break-in period takes up to 100 gallons
of material.
Faulty transducer Replace transducer.
Excessive paint leakage into throat
packing nut
Throat packing nut is loose.
Remove throat packing nut spacer. Tighten throat
packing nut just enough to stop leakage.
Throat packings are worn or damaged. Replace packings. See manual 309277.
Displacement rod is worn or damaged. Replace rod. See manual 309277.
Fluid is spitting from gun
Air in pump or hose
Check and tighten all fluid connections. Reprime pump.
See operation manual.
Tip is partially clogged. Clear tip. See manual 311254.
Fluid supply is low or empty.
Refill fluid supply. Prime pump. See operation manual.
Check fluid supply often to prevent running pump dry.
Problem Cause Solution