Graco 257100 Operation page 17

Low or Fluctuating Output (continued)
PROBLEM
Motor runs and pump strokes
Motor runs but pump does not
stroke
Motor intermittently stops while
applying material
Electrical Short
PROBLEM
Building circuit breaker opens as
soon as power switch is turned on.
CAUTION
Any short in any part of the motor
power circuit will cause the control
circuit to inhibit drywall feed pump
operation. Correctly diagnose and
repair all shorts before checking
and replacing control board.
Building circuit breaker opens as
soon as unit is plugged into outlet
and unit is NOT turned on.
Drywall feed pump quits after unit
operates for 5 to 10 minutes.
3A0245A
CAUSE
No material supply.
Loose fittings.
Intake valve ball and piston ball are not seat-
ing properly.
Leaking around throat packing nut which may
indicate worn or damaged packings.
Pump rod damage.
Displacement pump pin (damaged or miss-
ing).
Connecting rod assembly is damaged.
Gears or drive housing.
CAUSE
Electrical wiring insulation damaged, termi-
nals fit loose or are damaged. Also wires
between motor control and motor.
Motor armature is shorted.
Motor control board.
Basic Electrical Problems, see page 15.
For damaged or pinched wires in pressure
control.
Basic Electrical Problems.
Check electrical supply with volt meter.
Meter must read:
210-255 Vac for 220-240 Vac models;
85-130 Vac for 100-120 Vac models.
SOLUTION
Refill hopper and re-prime pump.
Clean hopper strainer.
Tighten; use thread sealant or sealing
tape on threads if necessary.
Remove intake and piston valves and
clean. Check balls and seats for nicks or
obstructions; replace if necessary, page
18. Also check piston valve seat for
hardened material or nicks and replace
if necessary. Clean hopper before using
to remove particles that could clog
pump.
Replace packing, page 18.
Repair pump.
Replace pump pin if missing. Be sure
retainer spring (76) is fully in groove all
around connecting rod.
Replace connecting rod assembly.
Inspect drive housing assembly and
gears for damage. Replace if needed.
See RF Problems, page 18.
SOLUTION
Repair or replace damaged wiring or
terminals. Securely reconnect all
wires.
Replace motor. Inspect windings for
burns. Perform motor control board
diagnosis.
Replace with a new control board if
necessary. Perform motor control
board diagnosis.
Perform necessary procedures.
Replace damaged parts.
Perform necessary procedures.
If voltage is too high, do not operate
drywall feed pump until corrected.
Troubleshooting
17