Graco 278680, Instructions Manual, Page: 13 / 28

Troubleshooting
332257A 13
Motor runs and pump strokes Low paint supply. Refill and reprime pump.
Intake strainer clogged. Remove and clean, then reinstall.
Suction tube or fittings loose. Tighten; use thread sealant or
sealing tape on threads if necessary.
See if intake valve ball and piston ball
are seating properly. See pump
manual. Remove intake valve and clean.
Check balls and seats for nicks,
replace if necessary. Strain paint
before using to remove particles that
could clog pump. See pump manual.
Leaking around throat packing nut
which may indicate worn or damaged
packings. See pump manual. Replace packings. Also check piston
valve seat for hardened paint or nicks
and replace if necessary. Tighten
packing nut/wet-cup. See pump
manual.
Pump rod damage. Replace pump, page 15.
Motor runs but pump does not stroke Displacement pump pin damaged or
missing.
Replace pump pin if missing. Be sure
retainer spring is fully in groove all
around connecting rod, page 15.
Connecting rod assembly damaged. Replace connecting rod assembly.
See pump manual.
Gears or drive housing, page 17. Inspect drive housing assembly and
gears for damage and replace if
necessary, page 17.
Motor is hot and runs intermittently Determine if sprayer was operated at
high pressure with small tips, which
causes low motor RPM and
excessive heat buildup. Decrease pressure setting or
increase tip size.
Be sure ambient temperature where
sprayer is located is not more than
90°F (32.22°C) and sprayer is not
located in direct sun. Move sprayer to shaded, cooler area
if possible.
Type of Problem
What to Check
(if check is OK, go to next)
What to Do
(When check is not OK, refer to this
column)