21
307–920
MOTOR IS HOT & RUNS INTERMITTENTLY
1. Decrease pressure setting or increase
tip size.
2. Move sprayer to shaded, cooler area if
possible.
3 Turn of f sprayer whenever you stop
spraying for a while and relieve fluid
pressure.
1. Check to see if sprayer has been operating
at high pressure with small tips, which
causes low motor RPM and results in exces-
sive heat build up.
2. Be sure ambient temperature where sprayer
is located is no more than 90 F and sprayer is
not located in direct sun.
3. Check to see if sprayer has been left in a
stalled condition (sprayer turned on, pres-
surized, but not operating) for long periods of
time.
WHAT TO CHECK
If check is OK, go to the next check.
WHAT TO DO
If check is not OK, refer to this column.
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 immedi-
ately. Correctly diagnose and
repair all shorts before check-
ing and replacing bridge.
1. Check all electrical wiring for damaged insula-
tion, and all terminals for loose fit or damage.
Also check wires between pressure control
and motor which are encased in conduit (22).
See page 35.
2. Check for missing inspection plate gasket (see
page 25), bent terminal forks or other metal to
metal contact points which could cause a
short.
3. Check motor armature for shorts by using an
armature tester (growler) or perform spin test.
See page 22. Inspect windings for burns.
4. Check bridge (308) by substituting with a good
bridge or by performing bridge test. See page
23.
CAUTION:
Do not perform this check until arma-
ture is determined to be good. A bad armature will
immediately burn out a good bridge.
1. Repair or replace any damaged wir-
ing or terminals. Securely reconnect
all wires.
2. Correct faulty conditions.
3. Replace motor. See page 34.
4. Replace bridge. See page 27.
1. Check ‘Basic Electrical Problems’ on page
16.
2. Check ON/OFF switch (302). See page 26.
Be sure the sprayer is unplugged! Disconnect
wires from switch. Check switch with ohmme-
ter. The reading should be infinity with the ON/
OFF switch OFF, and zero with the switch ON.
CAUTION:
A short in the motor circuit will burn the
bridge out immediately, which in turn usually
causes the ON/OFF switch to fail in the closed
mode.
2. Replace ON/OFF switch. See page
26.
Building circuit
breaker
opens as soon as sprayer is
plugged into outlet and
sprayer is NOT turned on.
WHAT TO CHECK
If check is OK, go to the next check.
TYPE OF PROBLEM
WHAT TO DO
If check is not OK, refer to this column.
Sprayer circuit breaker opens
after sprayer operates for only 5 to
10 minutes.
1. Check electrical supply with volt meter. Meter
should read 105 to 125 VAC.
2. Check tightness of pump packing nut. Over-
tightening nut tightens packings on rod, re-
stricts pump action, and damages packings.
3. Check stall pressure. Remove the plug from
the top of the fluid filter, and install a 5000 psi
fluid–filled pressure gauge. See page 31.
Plug in and turn on sprayer. Slowly increase
pressure setting to maximum. pump should
stall at 2800–3000 psi. T urn off and unplug
sprayer.
4. After determining that there is no short in sys-
tem, reset circuit breaker button.
1. If voltage is too high, do not operate
sprayer until corrected.
2. Loosen packing nut. Check for leaking
around throat. Replace pump pack-
ings, if necessary. See page 36.
3. Calibrate pressure control. See page
31.
4. If circuit breaker continues to open (but-
ton pops up), replace the circuit
breaker. See page 27.
Summary of Contents for 231-081
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