Graco ULTRA 500 Instructions-Parts List Manual page 17

TYPE
OF
PROBLEM TYPE
OF
PROBLEM
NO OUTPUT
(Continued)
Motor runs but pump does
not stroke
EXCESSIVE PRESSURE
FLUCTUATIONS
Spray pattern variations.
MOTOR IS HOT
e
RUNS IMERMI'ITENTLY
Motor runs but pump does
not stroke
FLUCTUATIONS
WHAT TO CHECK
If
check Is OK, go to next check
.
Check to see If Intake valve ball and piston
ball are seating properly. See manual
307-793.
#.
Check for leaking around throat packing nut
which may indicate worn or damaged pack-
1ngs.See manual 307-793.
.
Check displacement pump connecting rod
pin. See page 28.
I. Check connecting rod assembly for damage.
See page 28.
I.
Be sure crank in drive housing rotates: plug
in sprayer and turn on momentarily to check.
Turn
off
end unplug sprayer. See page 28.
I. Be sure both
G1 and G2 leads from bridge
connected. See page
25.
(308) to circuit board (23) are firmly
!.
Check stall pressure. Refer to Calibration
I . Check bourdon tube flag end detector posi-
tion. Turn pressure setting to maximum: flag
should not drag or bind In optical detector
slot of circuit board.
procedure on page 27.
fClRCUlTBOARD
r
VIEW OF OPTICAL DETECTOR AND FLAG
1. Check circuit board
(231
by substituting with
i. Check LOW OUTPUT section on page 16.
a good board.
Sea
page 25.
I, Check to see if sprayer has been operating
ai
high pressure with small tips, which causes
low motor RPM and results in excessive heal
build up.
I .
Check to see if ambient temperature where
sprayer is located is more than W F 132%)
or if sprayer Is located in direct sun.
3, Check to see if sprayer has been laft In a
Stalled condition (sprayer turned on,
pressurized. but not operating) for long
periods of time.
WHAT TO DO
When check
Is
not OK refer to this columr
..
Remove Intake valve and clean. Check balls
and seats for nicks: replace if necessary. Sef
manual
307-793.
I .
Replace packings. See manual 307-793. Also
check piston valve seat for hardened paint
0 1
nicks and replace
if
necessary.
.
Replace pin if missing. Be sure retainer
spring is fully in groove all around connect-
ing rod. See page 28.
.
Replace connecting rod assembly. See page
.
Check drive housing assembly for damage
28.
and replace if necessary. See page
28.
.
Reconnect securely. See page
24
end
26.
,.
Calibrate pressure control. See page 27
,.
Carefully bend flag into alignment with
detector slot to see if that corrects problem.
If not, replace bare pressure control
assembly (301)'. .Calibrate pressure control
after reassembly.
..
Replace circuit board.
See
page
2 5 ,
.
Decrease pressure setting or increase tip
size.
!.
Move sprayer to shaded, cooler area if
possible.
I. Turn off sprayer whenever you stop sprayins
for a while and relieve fluid Dressura.
'When rnplecing the bare
pressure control
box
13011.
remove the circuit board, bridge,
circuit board.
end
electrical
hardware and reinstall in
the new barn box.
Troubleshooting continuedon nextpage