Graco 231–034 Instructions And Parts List page 20

5 There is no fluid output.
PROBLEM
The motor operates and
the pump cycles.
The motor operates but
the pump does not cycle.
6 There are excessive fluctuations of the pressure.
PROBLEM
There are variations in
the spray pattern.
WHAT TO CHECK
If check is OK, go to next check
1. Check paint supply.
2. Check for clogged intake strainer.
3. Check for loose suction tube or fittings.
4. Check to see if intake valve ball and piston ball
are seating properly. See page 37.
5. Check for leaking around throat packing nut
which may indicate worn or damaged pack-
ings. See page 37.
1. Check displacement pump connecting rod pin
(43). See Fig. 29, page 36.
6. Check connecting rod assembly (68) for dam-
age. See page 32.
7. Be sure crank in drive housing rotates; plug in
sprayer and turn on briefly to check. Turn off
and unplug sprayer. See page 33.
WHAT TO CHECK
If check is OK, go to next check
1. Be sure both G1 and G2 leads from bridge
(308) to circuit board (71) are firmly connected.
See Fig. 17, page 27.
2. Check maximum working pressure adjustment.
Refer to Pressure Control Adjustment on page
30.
3. Check bourdon tube flag (B) and the detector
(A) position. Turn pressure setting to maxi-
mum; flag should not drag or bind in optical
detector slot of circuit board (71).
4. Check circuit board (71) by substituting with a
good board. See page 28.
5. Check section 4 on page 19.
WHAT TO DO
When check is not OK refer to this column
1. Refill and reprime pump.
2. Remove and clean, then reinstall.
3. Tighten; use thread sealant or sealing tape
on threads if necessary.
4. Remove intake valve and clean. Check
balls and seats for nicks; replace if neces-
sary. See page 36. Strain paint before using
to remove particles that could clog the
pump.
5. Replace packings. See page 37. Also check
piston valve seat for hardened paint or nicks
and replace if necessary. Tighten the pack-
ing nut/wet-cup.
1. Replace pin if missing. Be sure retainer
spring (42) is fully in groove all around con-
necting rod. See Fig. 29, page 36.
2. Replace connecting rod assembly. See
page 32.
3. Check drive housing assembly for damage
and replace if necessary. See page 33.
WHAT TO DO
When check is not OK refer to this column
1. Reconnect securely. See page 27.
2. Perform pressure control adjustment. See
page 30.
3. Carefully bend flag into alignment with de-
tector slot to see if that corrects problem. If
not, replace bare pressure control assembly
(301). Perform pressure control adjustment
after reassembly.
71
A
B
Replace circuit board. See page 28.