Vestil GLT-4000 - Manual (Page 12)

12
Observation Possible Cause Remedy
5.) Table lowers too slowly when loaded.
6.) Table lowers too quickly.
7. Table raises then lowers slowly.
8. Table has raised, but does not lower.
a. Remove Solenoid Valve and clean filter.
b. Correct as necessary. (In case of pipe,
check for obstruction in line.)
c. Remove and clean Flow Control Valve.
(Refer to Hydraulic Section of Owner's
Manual p. 10-11).
d. Align cylinders correctly.
e. Remove and clean Velocity Fuse. (Refer to
Hydraulic Section of Owner's Manual p. 10-
11).
a. Correct as necessary.
b. Remove and clean Check Valve. (Refer to
Hydraulic Section of Owner's Manual p. 10-
11).
c. Remove Flow Control Valve from the
Valve Block and clean. (Refer to Hydraulic
Section of Owner's Manual p. 10-11).
a. See 2(a).
b. Remove and clean Check Valve. (Refer to
Hydraulic Section of Owner's Manual p. 10-
11).
c. Correct as necessary.
d. Replace packings. (Consult Factory for
replacement parts.)
a. Check and replace.
b. Correct as necessary. (Refer to Electrical
Section of Owner's Manual.)
c. Lightly tap down the Solenoid Coil body to
seat it properly. (DO NOT hit coil hard as it
will permanently damage the internal
stem). DO NOT remove the Solenoid
Valve from the Block as the unit will come
down at a dangerous speed.
d. Remove and replace. (Refer to Electrical
Section of Owner's Manual.
e. Raise table and remove the safety bar, or
whatever object is blocking the down
travel, then press the down button.
f. See 2(e).
g. To unlock, re-pressurize the hydraulic
system.
h. Refer to Velocity Fuse Section of the
Owner's Manual p.8.
a. Down Valve filter clogged.
b. Pinched tube or hose.
c. Foreign material in Flow Control Valve.
d. Binding cylinders
e. Foreign material in Velocity Fuse.
a. Leaking hoses and/or cracked fittings.
b. Check valve is stuck open.
c. Foreign material stuck in Flow Control
Valve. (In this case, table lowers initially at
a normal rate then speeds up as the
platform descends.)
a. Down Solenoid Valve may be incorrectly
wired or is stuck open due to dirt.
b. Check Valve may be stuck open.
c. Check for leaking hoses, fittings, pipes.
d. Cylinder packings may be worn or
damaged.
a. Blown electrical fuse.
b. Incorrect Down Solenoid Valve wiring.
c. Down Solenoid Valve is stuck.
d. Faulty Down Solenoid Coil.
e. Maintenance safety bar, or some other
object blocking down trave.
f. Binding cylinders.
g. In case of excessive down speeds, the
Velocity Fuse will become operative and
shut off the oil flow from the cylinders, thus
the platform will remain stationary.
h. Check if the Limit Switch is inoperative and
the platform has raised all the way so that
the mechanical stops are engaged. If
mechanical stops are engaged, the
Velocity Fuse has been locked up.