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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.
The pump' s speed is
erratic or accelerated.
*
To determine if the fluid hose or gun is obstructed, relieve the pressure. Disconnect the fluid hose and place a
container at the pump fluid outlet to catch any fluid. Turn on the air just enough to start the pump. If the pump
starts when the air is turned on, the obstruction is in the fluid hose or gun.
NOTE: If you experience air motor icing, call your Graco distributor.
Troubleshooting Chart
CAUSE
Valves are closed or clogged.
The fluid hose or gun is obstructed.
Fluid has dried on the displacement rod. Clean the rod; always stop the pump at the bottom
Air motor parts are dirty, worn, or dam-
aged.
The air line is restricted or the air supply
is inadequate. V alves are closed or
clogged.
The fluid hose or gun is obstructed;
the fluid hose ID is too small.
Worn packings in the displacement
pump.
Air motor parts are dirty, worn, or dam-
aged.
Held open or worn intake valve.
Held open or worn intake valve.
Held open or worn piston valve
or packings.
The fluid supply is exhausted.
Held open or worn piston valve
or packings.
Held open or worn intake valve.
1. Relieve the pressure.
2. Check all possible causes and problems before
disassembling the pump.
SOLUTION
Clear the air line; increase the air supply.
Check that the valves are open.
Clear the hose or gun*;
use a hose with a larger ID.
of its stroke; keep the wet-cup 1/3 filled with a
compatible solvent.
Clean or repair the air motor;
see the separate motor manual.
Clear the air line; increase the air supply.
Check that the valves are open.
Clear the hose or gun*;
use a hose with a larger ID.
Replace the packings.
Clean or repair the air motor;
see the separate motor manual.
Clear or service the intake valve.
Clear or service the intake valve.
Clear the piston valve; replace the packings.
Refill the supply and prime the pump.
Clear the piston valve; replace the packings.
Clear or service the intake valve.
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