Vestil EHLTT Series, Owner'S Manual

Page: 10 / 16

10
Observation Possible Cause Remedy
6.) Table lowers too quickly.
7.) Table raises then lowers slowly.
8.) Table has raised, but does not lower.
a. Correct as necessary.
b. Remove and clean check valve. (Refer to Hydraulic
Section of Owner's Manual).
c . Remove flow control valve from the valve block and
clean. (Refer to Hydraulic Section of Owner's
Manual).
a. See 2(a).
b. Remove and clean check valve. (Refer to Hydraulic
Section of Owner's Manual ).
c . Correct as necessary.
d. Replace packing. (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.
f . See 2(e).
g. To unlock, repressurize the hydraulic system by
jogging the motor.
h. Refer to velocity fuse section of the owner's manual
a. Leaking hoses and/or cracked fittings.
b. Check valve is stuck open. (The combination of a
stuck check valve and open solenoid valve will
cause excessive speeds.)
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 packing 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 travel.
f . Binding cylinders.
g. In case of excessive lowering 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 cylinders
are fully extended. If the cylinder(s) are stroked out,
the velocity fuse has been locked up
NOTES