307–758
21
MOTOR IS HOT AND RUNS INTERMITTENTLY
TYPE OF PROBLEM
WHAT TO CHECK
If check is OK, go to next check
WHAT TO DO
When check is not OK refer to this column
1. Determine if sprayer was operated at high
pressure with small tips, which causes low
motor RPM and excessive heat build up.
1. Decrease pressure setting or increase tip
size.
2. Be sure ambient temperature where sprayer
is located is no more than 90
F and sprayer
is not located in direct sun.
2. Move sprayer to shaded, cooler area, if
possible.
3. Determine if was sprayer turned on, pressur-
ized, but not operating for long periods of time.
3 Turn off sprayer whenever you stop spray-
ing for a while and relieve fluid pressure.
ELECTRICAL SHORT
TYPE OF PROBLEM
WHAT TO CHECK
If check is OK, go to next check
WHAT TO DO
When check is not OK refer to this column
Building circuit breaker opens
as soon as sprayer switch is
turned on.
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 (1).
See page 34.
1. Repair or replace any damaged wiring or
terminals. Securely reconnect all wires.
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.
2. Correct faulty conditions.
3. Check motor armature for shorts. Use an ar-
mature tester (growler) or perform spin test.
See page 22. Inspect windings for burns.
3. Replace motor. See page 34.
4. Check bridge (308) by substituting with a
good bridge or by performing bridge test. See
pages 23 or 27.
CAUTION: Do not check bridge until arma-
ture is determined to be good. A bad armature
will immediately burn out a good bridge.
4. Replace bridge. See page 27.
1. Check ‘Basic Electrical Problems’ on page
16.
2. Check ON/OFF switch (303) 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 burns
the bridge out immediately, which usually
causes the ON/OFF switch to fail in the closed
mode.
2. Replace ON/OFF switch. See page 26.
Sprayer circuit breaker opens
after sprayer operates for 5 to
10 minutes.
1. Check electrical supply with volt meter. Meter
should read 105 to 125 VAC.
1. If voltage is too high, do not operate
sprayer until corrected.
2. Check tightness of pump packing nut. Over-
tightening tightens packings on rod, restricts
pump action, and damages packings.
2. Loosen packing nut. Check for leaking
around throat. Replace pump packings, if
necessary. See page 36.
3. Check maximum working pressure adjust-
ment.
3. Perform Pressure Control Adjustment. See
page 30.
4. After determining that there is no short in sys-
tem, reset circuit breaker button.
4. If circuit breaker continues to open (button
pops up), replace the circuit breaker. See
page 27.
.
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.
Building circuit breaker
opens as soon as
sprayer is plugged into
outlet and sprayer is
NOT turned on.
