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Troubleshooting
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 12.
1. Relieve the pressure.
2. Check all possible problems and causes before
disassembling the pump.
PROBLEM
CAUSE SOLUTION
Pump fails to operate. Restricted air or hydraulic line or inade-
quate air supply; closed or clogged
valves.
Clear any obstructions; check that all valves are
open; increase pressure.
Obstructed fluid hose or gun/valve;
fluid hose ID is too small.
Open, clear*; use a hose with a larger ID.
Fluid dried on the displacement rod. Clean; always stop the pump at the bottom of its
stroke; keep the wet-cup 1/3 filled with a compat-
ible solvent.
Dirty, worn, or damaged motor parts. Clean or repair; see the separate motor manual.
Pump operates, but
output low on both
strokes.
Restricted air or hydraulic line or inade-
quate air supply; closed or clogged
valves.
Clear any obstructions; check that all valves are
open; increase pressure.
Obstructed fluid hose or gun/valve;
fluid hose ID is too small.
Open, clear*; use a hose with a larger ID.
Bleeder valve is open. Close the valve.
Air is leaking into the supply container. Check the ram plate seal.
Fluid is too heavy for pump priming. Use the bleeder valve (see page 13); use a ram.
Held open or worn intake valve or seals. Clear the valve; replace the seals.
Worn packings in the displacement
pump.
Replace the packings.
Pump operates, but
output low on down-
stroke.
Fluid too heavy for pump priming. Use the bleeder valve (see page 13); use a ram.
Held open or worn intake valve or seals. Clear the valve; replace the seals.
Pump operates, but
output low on upstroke.
Held open or worn piston valve or seals. Clear the valve; replace the seals.
THE TROUBLESHOOTING CHART IS CONTINUED ON PAGE 18.
* To determine if the fluid hose or gun is obstructed, follow the Pressure Relief Procedure on page 12. Dis-
connect the fluid hose and place a container at the pump fluid outlet to catch any fluid. Turn on the air or hydraulic
power just enough to start the pump. If the pump starts, the obstruction is in the fluid hose or gun.
NOTE: If you experience air motor icing, call your Graco distributor.