Vestil GLT-4000 - Manual (Page 11)

11
HYDRAULIC EQUIPMENT
Trouble Shooting Quick Reference Guide
(For further information contact the factory)
WARNING! BEFORE PERFORMING ANY MAINTENANCE WORK ALWAYS UNLOAD LIFT AND INSTALL MAINTENANCE SAFETY STOP(S)
Observation Possible Cause Remedy
1.) Table does not raise but pump is running
or humming.
2.) Table raises too slowly.
3.) Motor labors, or is excessively hot.
4.) "Spongy" or "Jerky" table operation. Do not
confuse spongy operation with small
surges caused by foreign material on table
wheel roller plate.
a. Motor may be single phasing (humming) if
three phase unit.
b. Voltage at motor terminals may be too low
to run pump at existing load.
c. Hose or hydraulic line is leaking.
d. Fluid level in reservoir is low.
e. Load exceeds capacity requirements.
Relief Valve is bypassing the fluid back
into the reservoir.
f. Suction filter is clogged, starving pump.
g. Suction line may be leaking air, due to
loose fittings.
h. Filler/Breather cap on tank may be
clogged.
i. Down Valve may be energized by faulty
wiring or stuck open.
j. Hydraulic pump may be inoperative.
a. Foreign material stuck in Down Solenoid,
causing some fluid to bypass back into
tank.
b. Foreign material clogging suction filter,
breather cap, or a pinched hose.
c. Low motor voltage.
d. Table overloaded.
e. Pump is inoperative.
a. Voltage may be low.
b. Incorrect wiring.
c. Oil starvation causes pump to bind. High
internal heat is developed. If this occurs,
pump may be permanently damaged.
d. Binding cylinders.
a. Fluid starvation.
b. Air in system.
a. Check wiring and overloads, fuses, etc.
Ascertain that all 3 phase lines are present
at the motor.
b. Measure voltage at motor terminals or as
near as possible, while pump is running
under load. If voltage is sufficient, check
for inadequate or incorrect wiring as this
can starve the motor. (Refer to chart in
Owner's Manual for recommendations.)
Correct as necessary.
c. Correct as necessary.
d. Add fluid. Refer to Owner's Manual for
proper fluid levels.
e. DO NOT CHANGE RELIEF VALVE
SETTING. Instead, reduce the load to
rated capacity.
f. Remove and clean.
g. Inspect all fittings for proper fit.
h. Remove and clean.
i. Remove Solenoid Valve. Check and clean.
(Refer to Hydraulic Section of Owner's
Manual p.10-11).
j. Disconnect hydraulic line at power unit.
Put pressure line in a large container and
cycle pump. If no output, check the pump
motor coupline, which may be defective,
and correct as necessary. If pump is worn,
consult factory for replacement parts
service.
a. Lower the platform. Remove the Solenoid
Valve and clean. (Refer to Hydraulic
Section of Owner's Manual p. 10-11).
b. Correct as necessary. (See also, 1(f), (h).
c. See 1(b).
d. See 1(e).
e. See 1(j).
a. See 1(b).
b. Check that one leg of the motor lines is not
connected to ground.
c. See 1(d), (f), (g), (h), (j).
d. Align cylinders correctly.
a. See 1(d), (f), (g), (j).
b. See air bleed procedure p.9.