Troubleshooting
308360D
11
Troubleshooting
1. Follow
checking or repairing the pump.
2. Check all possible problems and causes before
disassembling pump.
To determine if the fluid hose or gun is obstructed:
1. Perform the
2. Disconnect the fluid hose and place a container at
the pump fluid outlet to catch any fluid.
3. 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 Graco
Technical Assistance.
Problem
Cause
Solution
The pump fails to operate.
The air line is restricted or the air
line is inadequate; valves are closed
or clogged.
Clear the line; increase the air
supply. Check that the valves are
open.
The fluid hose or gun is obstructed;
the fluid hose ID is too small.
Open, clear*; use a hose with a
larger ID.
Fluid has dried on the displacement
rod.
Clean the rod; always stop the pump
at the bottom of its stroke; keep the
wet-cup 1/3 filled with a compatible
solvent.
Motor parts are dirty, worn, or
damaged.
Clean or repair; see the separate
motor manual.
The pump operates, but the output
is low on both strokes.
The air line is restricted or the air
line is inadequate; valves are closed
or clogged.
Clear the line; increase the air
supply. Check that the valves are
open.
The fluid hose or gun is obstructed;
the fluid hose ID is too small.
Open, clear*; use a hose with a
larger ID.
The packings in the displacement
pump are worn.
Replace the packings.
The pump operates, but the output
is low on the downstroke.
The intake valve is held open or
worn.
Clear the valve; service.
The pump operates, but the output
is low on the upstroke.
The piston valve or packings are
held open or worn.
Clear the valve; replace the
packings.
Erratic or accelerated pump speed.
The fluid supply is exhausted.
Refill the supply and prime the
pump.
The piston valve or packings are
held open or worn.
Clear the valve; replace the
packings.
The intake valve is held open or
worn.
Clear the valve; service.
