Graco Inc. 261820 Manuale Utente
Advanced Troubleshooting
312667B
21
General Problem: Low or Fluctuating Output
Specific Problem
Cause
Solution
Pump cycles, but output is low or
surging.
surging.
See Basic Troubleshooting,
page 11.
page 11.
Worn or obstructed inlet and
outlet valves.
outlet valves.
Check for worn pump valves as follows:
Prime sprayer with paint. Turn the Prime/Spray valve
to SPRAY position. Turn pressure control fully
clockwise.
to SPRAY position. Turn pressure control fully
clockwise.
Trigger spray gun briefly.
When spray gun trigger is released pump should
cycle momentarily and stop.
cycle momentarily and stop.
If pump continues to cycle, pump valves may be
worn or obstructed.
worn or obstructed.
For replacement inlet and outlet valve kits, see List
of Kits, page 26.
of Kits, page 26.
Prime/Spray valve is leaking out
drain line when Prime/Spray
valve is in SPRAY position.
drain line when Prime/Spray
valve is in SPRAY position.
Check Prime/Spray valve for debris trapped on seat
and for worn parts. Torque to 130-180 in-lb
(15.8-18.1 N•m). Replace if parts are worn using
Prime/Spray Valve Kit, page 26.
and for worn parts. Torque to 130-180 in-lb
(15.8-18.1 N•m). Replace if parts are worn using
Prime/Spray Valve Kit, page 26.
Voltage from electrical outlet is
too low. Low voltages reduce
sprayer performance.
too low. Low voltages reduce
sprayer performance.
Check voltage of outlet. Meter must read 85 to 130V
AC.
AC.
Extension cord is too long or not
heavy enough gauge.
heavy enough gauge.
Replace extension cord.
See Grounding and Electrical Requirements,
page 6.
page 6.
Leads from motor or pressure
switch to control board are
damaged, loose, pinched, or
overheated.
switch to control board are
damaged, loose, pinched, or
overheated.
Be sure terminals are centered and firmly
connected. Inspect for pinched wiring and wiring
insulation and terminals for signs of overheating.
Replace any loose terminals or damaged wiring.
Securely reconnect terminals.
connected. Inspect for pinched wiring and wiring
insulation and terminals for signs of overheating.
Replace any loose terminals or damaged wiring.
Securely reconnect terminals.
Motor brushes are worn.
Check length of BOTH brushes (brushes do not
wear evenly on both sides of the motor). Brush
length must be 0.25 in. (6.4mm). If brushes are worn
replace motor using Motor Kit, page 26.
wear evenly on both sides of the motor). Brush
length must be 0.25 in. (6.4mm). If brushes are worn
replace motor using Motor Kit, page 26.
Motor brush springs are broken.
If springs are broken, replace motor using Motor Kit,
page 26.
page 26.
Motor brushes are binding in
brush holders.
brush holders.
Clean brush holders. Remove carbon dust with small
cleaning brush.
cleaning brush.
Motor stops before sprayer
reaches correct pressure (stall
pressure is too low).
reaches correct pressure (stall
pressure is too low).
Replace pressure control using Pressure Control
Switch Kit, page 26.
Switch Kit, page 26.
Control board is damaged.
CAUTION: Do not perform
control board diagnostics until
you have determined the
armature is good. A damaged
armature can burn out a good
control board.
control board diagnostics until
you have determined the
armature is good. A damaged
armature can burn out a good
control board.