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WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 10.
PROBLEM
The pump fails to oper-
ate.
The pump operates,
but the output is low on
both strokes.
The pump operates,
but the output is low on
the downstroke.
The pump operates,
but the output is low on
the upstroke.
Erratic or accelerated
pump speed.
*
To determine if the fluid hose or gun is obstructed, follow the Pressure Relief Procedure on page 10. Discon-
nect 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 when the air or hydraulic power is turned on, the ob-
struction is in the fluid hose or gun.
NOTE: If you experience air motor icing, call your Graco distributor.
Troubleshooting Chart
CAUSE
Restricted air/hydraulic line or an inade-
quate air/hydraulic supply; closed or
clogged valves.
Obstructed fluid hose or gun;
the fluid hose ID is too small.
Fluid has dried on the displacement rod. Clean the rod; always stop the pump at the bottom
Dirty, worn, or damaged motor parts.
Restricted air/hydraulic line or an inade-
quate air/hydraulic supply; closed or
clogged valves.
Obstructed fluid hose or gun;
the fluid hose ID is too small.
Worn packings in the displacement
pump.
Held open or worn intake valve.
Held open or worn piston valve or pack-
ings.
Exhausted fluid supply.
Held open or worn piston valve or pack-
ings.
Held open or worn intake valve.
1. Relieve the pressure.
2. Check all possible causes and problems before
disassembling the pump.
SOLUTION
Clear the line; increase the air/hydraulic supply.
Check that the valves are open.
Open, clear*; use a hose with a larger ID.
of its stroke;
keep the wet-cup 1/3 filled with a compatible sol-
vent.
Clean or repair; see the separate motor manual.
Clear the line; increase the air/hydraulic supply.
Check that the valves are open.
Open, clear*; use a hose with a larger ID.
Replace the packings.
Clear the valve; service.
Clear the valve; replace the packings.
Refill the supply and prime the pump.
Clear the valve; replace the packings.
Clear the valve; service.
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