Troubleshooting; Mechanical/Fluid Flow - Graco Ultra Max II 795 Repair Manual

Relieve pressure; page 5.

Mechanical/Fluid Flow

TYPE OF PROBLEM
Low Output or Pressure
Motor runs but pump does not
stroke
6
309941

Troubleshooting

WHAT TO CHECK
If check is OK, go to next check
1. For worn spray tip.
2. Spray tip clogged.
3. Paint supply.
4. Intake strainer clogged.
5. To see if intake valve ball and piston ball are seat-
ing properly.
6. Suction hose connections.
7. Filter clogged.
8. Prime valve leaking.
9. Verify pump does not continue to stroke when
gun trigger is released. (Prime valve not leak-
ing.)
10. Leaking around throat packing nut which may
indicate worn or damaged packings. See page
20.
11. Pump rod damage.
12.Low stall pressure.
1. Displacement pump pin (32) (damaged or miss-
ing), page 20.
2. Connecting rod assembly (43) for damage,
page 16.
3. Gears or drive housing, page 16.
WHAT TO DO
When check is not OK refer to this column
1. Follow Pressure Relief Procedure Warn-
ing, then replace tip. See your separate
gun or tip manual.
2. Relieve pressure. Check and clean spray
tip.
3. Refill and reprime pump.
4. Remove and clean, then reinstall.
5. Remove intake valve and clean. Check
balls and seats for nicks; replace if neces-
sary, page 20. Strain paint before using to
remove particles that could clog pump.
6. Tighten any loose connections. Check for
missing or damaged seals.
7. Relieve pressure. Check and clean filter.
8. Relieve pressure. Repair prime valve.
9. Service pump. See page 20.
10.Replace packings, page 20. Also check
piston valve seat for hardened paint or
nicks and replace if necessary. Tighten
packing nut/wet-cup.
11. Repair pump, page 20.
12. Do either or both:
a. Turn pressure control knob fully
clockwise. Make sure pressure
control knob is properly installed to
allow full clockwise position.
b. Try a new pressure transducer.
1. Replace pump pin if missing. Be sure re-
tainer spring (31) is fully in groove all
around connecting rod, page 20.
2. Replace connecting rod assembly,
page 16.
3. Inspect drive housing assembly and gears
for damage and replace if necessary,
page 16.