Vestil ZLTT series - Manual (Page 14)

08/04
V ESTIL M FG . C O ./T&S E QPT . C O . 14 of 16
T ROUBLESHOOTING G UIDE -- M ODEL ZLTT
Before performing any task, always lower the platform fully to the floor and disconnect the power supply.
Consult the factory for problems at time of installation, or for any problems not addressed below.
Problem: Possible cause(s): Action:
Power unit doesn’t run when one,
or either, “RAISE” button is
pressed.
Transformer fuse is blown.
No supply voltage.
Upper travel limit switch is
engaged or bad.
Bad connection in control circuit.
Bad control transformer.
Open motor relay coil.
Test with meter; replace if bad.
Test with meter. Check fuses,
breakers, and overloads to
determine the cause.
Inspect and test switch.
Replace if bad.
Test all parts of circuit with
meter.
Check for 24 VAC; replace if
bad.
Test with meter; replace if bad.
Motor runs properly, platform
doesn’t move. Motor and
pump not noisy.
Motor rotation is wrong.
Pump has failed.
Fluid level is low. Verify motor shaft rotates CCW.
Consult factory for replacement.
Ensure reservoir is filled.
Motor or control enclosure hums,
chatters, or buzzes, or some
type of squeal can be heard;
the platform does not move, or
the platform moves only slowly.
See second item above, for when
platform doesn’t raise.
Excess voltage drop to motor,
due to power wire size too
small, wire run to long, or
incoming voltage too low.
Motor is “single-phasing”.
Pressure relief opening at full
pressure.
Contamination holding open the
lowering valve or the check
valve.
Same as above.
Check power installation for
adequacy. Check incoming
voltage while motor is running.
Correct any problem found.
Determine cause of loss of
voltage on one phase; correct.
Check for structural damage of
the legs, platform, etc.
Check for platform overload
condition.
Remove and inspect. Clean per
instructions in this manual.
Platform raises, then drifts down. See last paragraph, above. Same as last item, above.
Platform lowers too quickly. See above.
Flow control spool is stuck. Same as above.
See below.
Platform lowers too slowly. Flow control spool is stuck.
Pinched hose.
Velocity fuse locking (platform
only slowly creeps down).
Remove solenoid valve; push
down on the center of the flow
spool to ensure it moves freely.
Check pressure, supply, and
return hoses for kinks.
Same as for jerky platform
motion.
Platform won’t lower. Velocity fuse locking.
Control transformer fuse blown.
No supply voltage.
Valve solenoid is bad.
Bad connection in control circuit.
Physical blockage of the
structure.
Solenoid valve or suction hose
screen plugged.
Same as for jerky platform
motion.
Test with meter; replace if bad.
Test with meter. Check for
cause of power loss.
Check with multimeter on diode-
check function. (Reading for
ohms will not provide an
accurate test of the coil.)
Test all parts of circuit with
meter.
Inspect for foreign material or
objects under the leg set.
Remove and inspect. Clean per
instructions in this manual.
Spongy or jerky platform motion. Excessive air in the hydraulic
cylinders.
Bleed air per procedure
described in this manual.