Graco 3A4133 Operation - Repair - Parts page 28

Troubleshooting
Problem
Pump output is low
Motor runs but pump does not
stroke
28
What to Check
If check is OK, go to next
check
Pump rod damage.
Low stall pressure.
Piston packings are worn or
damaged.
O-ring in pump is worn or
damaged.
Intake valve ball is packed with
material.
Large pressure drop in hose
with heavy materials.
Check extension cord for
correct size.
Loose motor brushes and
terminals.
Worn motor brushes. (Brushes
must be 1/2 in. [13mm]
minimum length).
Broken and misaligned motor
brush springs. Rolled portion of
spring must rest squarely on
top of brush.
Motor brushes are binding in
brush holders.
Connecting rod assembly
damaged. See pump manual.
Gears or drive housing
damaged.
What to Do
When check is not OK,
refer to this column
Repair pump. See pump
manual.
Turn pressure knob fully
clockwise. Make sure pressure
control knob is properly
installed to allow full clockwise
position. If problem persists,
replace pressure transducer.
Replace packings. See pump
manual.
Replace o-ring. See pump
manual.
Clean intake valve. See pump
manual.
Reduce overall length of hose.
See Extension Cords, page
11.
Tighten terminal screws.
Replace brushes if leads are
damaged.
Replace brushes.
Replace spring if broken.
Realign spring with brush.
Clean brush holders, remove
carbon dust with a small
cleaning brush. Align brush
lead with slot in brush holder to
assure free vertical brush
movement.
Replace connecting rod
assembly. See pump manual.
Inspect drive housing
assembly and gears for
damage and replace if
necessary.
3A4187C