Vestil AHLT - Manual (Page 9)

9
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 packings. (Consult Factory for replacement
parts.)
a. 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.
b. Remove and replace. (Refer to Electrical Section of
Owner's Manual.)
c. Raise table and remove the safety bar, or whatever
object is blocking the down travel, then press the down
button.
d. See 2(e).
e. To unlock, re-pressurize the hydraulic system.
f. 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 Soleniod 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 packings may be worn or damaged.
a. Down Solenoid Valve is stuck.
b. Faulty Down Solenoid Coil.
c. Maintenance safety bar, or some other object
blocking down trave.
d. Binding cylinders.
e. 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.
f. 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.
Notes: