Graco A Series Instructions-Parts List Manual page 16

Intermediate Problem Solving
TYPE OF PROBLEM
Drain Valve Leaks
Transducer Leaks
No Output: Motor Runs
And Pump Strokes
No Output: Motor Runs
But Pump Does Not
Stroke
Troubleshooting
WHAT TO CHECK
If check is OK, go to next check
6. Check motor brushes. See What To Check,
item 4, on page 14.
7. Check motor start board (47) by substituting
with a good board.
CAUTION: Do not perform this check until mo-
tor armature is determined to be good. A bad
motor armature can burn out a good board.
8. Check motor armature for shorts by using an
armature tester (growler) or perform motor
test. See page 19.
1. Check for correct torque and/or worn parts.
Check for debris trapped on seat.
1. Slight leakage is normal.
1. Check paint supply.
2. Check for clogged intake strainer.
3. Check for loose siphon tube or fittings. See
page 22.
4. Check to see if intake valve ball and piston ball
are seating properly. See page 22.
5. Check for leaking around throat packing nut
which may indicate worn or damaged packings.
See page 22.
6. Release gun trigger. Observe resting position of
pump rod (107).
1. Check displacement pump connecting rod pin
(17). See page 22.
2. Check connecting rod assembly (15) for dam-
age. See page 28.
3. Be sure crank in drive housing rotates; plug in
sprayer and turn on briefly to check. Turn off
and unplug sprayer. See page 28.
WHAT TO DO
When check is not OK, refer to this column
6. See page 20.
7. Replace board. See page 27.
8. Replace motor. See page 26.
1. Tighten to 21 N.m. Clean valve and re-
place with new gasket (42a) and sealant
(42e). See page 32.
1. Periodically remove residue from its cyl-
inder port. See page 31.
1. Refill and reprime pump.
2. Remove and clean, then reinstall.
3. Tighten; use thread sealant on npt
threads of inlet tube (38). Check for dam-
aged o–ring (27).
4. Remove intake valve and clean. Check
ball and seat for nicks; replace as need-
ed. See page 22. Strain paint before us-
ing to remove particles that could clog
pump.
5. Replace packings. See page 23. Also
check piston valve seat for hardened
paint or nicks and replace if necessary.
Tighten packing nut/wet-cup.
6. If pump consistently comes to rest with
rod (107) fully extended, the piston
packings and/or piston valve may be
worn. Service the pump. See page 23.
1. Replace pin if missing. Be sure retainer
spring (18) is fully in groove all around
connecting rod.
2. Replace connecting rod assembly. See
page 28.
3. Check drive housing assembly for dam-
age and replace if necessary. See page
28.