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Troubleshooting
309674M 13
Motor runs but pump does not stroke Displacement pump pin damaged or
missing.
Replace pump pin if missing. Be sure
retainer spring is fully in groove all
around connecting rod, page 15.
Connecting rod assembly damaged. Replace connecting rod assembly.
See pump manual.
Gears or drive housing, page 17. Inspect drive housing assembly and
gears for damage and replace if
necessary, page 17.
Motor is hot and runs intermittently Determine if sprayer was operated at
high pressure with small tips, which
causes low motor RPM and
excessive heat buildup.
Decrease pressure setting or
increase tip size.
Be sure ambient temperature where
sprayer is located is not more than
90°F (32.22°C) and sprayer is not
located in direct sun.
Move sprayer to shaded, cooler area
if possible.
Building circuit breaker opens as
soon as sprayer switch is turned on
CAUTION
Any short in any part of the motor
power circuit will cause the control
circuit to inhibit sprayer operation.
Correctly diagnose and repair all
shorts before checking and replacing
control board.
All electrical wiring for damaged
insulation and all terminals for loose
fit or damage. Also, wires between
pressure control and motor. See
page 28.
Repair or replace any damaged
wiring or terminals. Securely
reconnect all wires.
For missing inspection plate gasket,
see page 26, bent terminal forks or
other metal to metal contact points
which case a short.
Correct faulty conditions.
Motor control board by performing
control board diagnostics. See page
14. If diagnostics indicate, substitute
with a good board.
CAUTION: Do not perform this check
until motor armature is determined to
be good. A bad motor armature can
burn out a good board.
Replace with a new pressure control
board. See page 26.
Building circuit breaker opens as
soon as sprayer switch is turned on
This problem only applies to Ultra,
Nova and STMax 395/495/595
model sprayers with brush motors.
They do not apply to UltraMax II,
Ultimate MX II and ST Max II
490/495/595 model sprayers.
Motor armature for shorts. Use an
armature tester (growler) or perform
spin test. See page14. Inspect
windings for burns.
Replace motor. See page 29.
Building circuit breaker opens as
soon as sprayer is plugged into outlet
and sprayer is NOT turned on.
Basic Electric Problems, page 9 of
Troubleshooting.
Perform necessary procedures.
Type of Problem
What to Check
(if check is OK, go to next)
What to Do
(When check is not OK, refer to this
column)