Graco ULTRA 500 Instructions-Parts List Manual page 18

TYPE OF PROBLEM
ELECTRICAL SHORT
Building circuit breaker opens
as soon as sprayer switch is
turned on.
CAUTION
Any short in any part of the
motor power circuit, which is
connected to the output side
of the bridge, will cause the
bridge to burn out immediate-
ly. Correcth, diagnose and
repair all shotts before check.
ing and replacing bridge.
as soon as sprayer is plugged
turned on.
into outlet and sprayer is NO1
Sprayer circuit breaker opens
after sprayer operates for only
5 to 10 minutes.
WHAT TO CHECK
WHAT TO DO
If
check
I s OK.
aa to next checkl
When check Is not OK refer to this column
1. Check all electrical wiring for damaged in- 1. Repair or replace any damaged wiring or ter-
sulation. and
all
terminals for loose
fit
or
damage. Be sure to check wires between
minals. Securely reconnect a 1 1 wires.
ed in conduit
( 2 2 1 .
See page 30.
pressure control and motor which are encas-
1.
Check for missing inspection plate gasket
2. Correct faulty conditions.
metal to metal contact points which could
(see page 22). bent terminal forks or other
cause a short.
3. Check motor armature for shorts by using an 3. Replace motor. See page 30.
armature tester (growler) or perform spin
test. See page 19. Inspect windings for
burns.
6 .
Check bridge (308) by substituting with a
4. Replace bridge. See page 24.
good bridge or by performing bridge test.
See page
20.
armature is determined to be good. A bed
CAUTION: Do not perform this check until
armature will immediately bum out
a good
bridae.
1. Check 'Basic Electrical Problems' on page 13.
2. Check ONlOFF switch
I 3 0 3 1
See page
23.
2. Replace ONlOFF switch. See page
23.
wires from switch and check switch with
Be sure the sprayer is unplugged1 Disconnect
ohm meter. The ohm meter should read in-
finity with the ON/OFF swltch OFF, and zero
with the switch ON.
burn the bridge out immediately, which in turn
CAUTION: A short in the motor circuit will
usually causea the ON/OFF switch to fail in the
closed mode.
1. Check electrical supply with volt meter.
2.
Loosen packing nut. Check for leaking
2. Check tightness of pump packing nut. Over-
1. If voltage is too high, do not operate sprayer
Meter should read 105 to 125 VAC. until corrected.
tightening nut tightens packings on rod,
packings.
around throat. Replace pump pecklngs. if
necessaly. See manual 307-793.
restricts pump action, and damages
the top of the fluid filter, arrd install a 5ooo
psi (350 bar1 fluid-filled pressure gauge. See
page 27. Plug in and turn on sprayer. Slowly
should stall
at 2550-2750 osi (178-195 bar).
increase pressure setting to maximum. Pump
3. Check
stall
pressure. Remove the plug from' 3. 'Calibrate pressure control.
See
page
27
Turn
off
and unplug spraier.
4. After determining that there is no short in
pops up), replace the circuit breaker. See system, resat circuit breaker button.
4.
If circuit breaker continues to open (button
page 24.
Troubleshooting continuedon nextpege
18
307-758