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Air in the hydraulic circuit can also cause the velocity fuse to activate although no failure has occurred. To reset the
velocity fuse, activate the pump by jogging the raise button. Immediately after resetting the velocity fuse, fully lower the
forks. Cycle the forks all the way to the top of the mast and back down several times to purge air from the system.
AIR BLEED PROCEDURE:
If the forks descend very slowly or do not lower, air probably is trapped in the hydraulic circuit and must be bled from
the system. To bleed air from the circuit:
1.) Completely unload and lower the forks.
2.) Loosen the bleeder screw at the top of the cylinder approximately 1/4 to 1/2 turn to allow trapped air to escape. Jog the
motor to push air out of the system.
3.) When air is no longer present in the cylinder, only clear hydraulic fluid will flow from the bleeder screw opening.
4.) Retighten the bleeder screw.
DC-POWERED HYDRAULIC SYSTEM TROUBLESHOOTING GUIDE
Before performing maintenance on this product, unload the forks and completely lower the carriage.
Observation
1. Unit does not raise, motor does not run
2. Unit does not raise but motor is running
or humming.
3. Unit rises too
slowly.
4. Motor labors or is excessively hot.
5.
"Spongy·
or "Jerky· unit operation.
6. Unit lowers too slowly when
Copyright 2017 Vestil Manufacturing Corp.
rev. 1/16/2017
Possible Cause
a. Low battery
b. All chassis connections to negative post
of battery not made well.
c.
Voltage at motor terminals might be too
low to run pump at existing load.
d. Fluid level in reservoir is low.
e. Load exceeds capacity
Relief valve is allowing hydraulic fluid to
flow back into the
f. Suction filter is clogged, starving pump.
g.
Suction line may be leaking air, due to
loose fittings.
h. Filter/Breather cap on tank might be
clogged.
i. Lowering solenoid valve might be
energized by faulty wiring or might be stuck
open.
j.
Hydraulic pump might be inoperative.
k.
Foreign material stuck in down solenoid
valve, causing some fluid to flow back into
the reservoir.
l. Foreign material clogging suction filter, or
breather cap, or a hose is pinched.
m. Low motor
n. Unit overloaded.
o. Inoperative pump.
p. Voltage may be low.
q. Oil starvation causing pump to bind &
high internal heat develops. If this occurs,
pump can be permanently damaged.
r. Binding cylinders.
s.
Fluid
starvation.
t. Air in
system.
loaded.
u. Lowering solenoid valve filter screen
clogged.
v. Pinched tube or
w.
Foreign material in flow control valve.
x. Binding
cylinders.
CBS, MANUAL.doc
voltage.
(Check light)
requirements.
reservoir.
voltage.
hose.
Remedy
a. Recharge battery
b.
Check and tighten or clean connections
if necessary.
c. Measure voltage at motor terminals or
as near as possible, while pump is running
under load. Check for loose connections.
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 tightness.
h. Remove and
clean.
i.
Remove lowering solenoid valve. Check
and clean.
(Refer
to "Lowering Solenoid
Valves".)
j. Disconnect hydraulic line at power unit.
Put pressure line in a large container and
operate
the
pump. If no
output,
pump motor coupling which may be
defective, and correct as
necessary.
pump is
worn,
consult factory for
replacement parts.
k. Lower the
deck.
Remove the down
solenoid valve and
clean.
(Refer to
Hydraulic Section of Owners Manual).
l.
Correct as necessary. (See
(h)).
m.
See 2 (b)
n.
See 2 (e)
o. See 2 (j)
p. See 2 (b)
q.
See 2 (d),
(f), (g),
(h), (j)
r.
Align cylinders correctly.
s.
See 2
(d),
(f),
(g), (j)
t.
See air bleed procedure (p. 15).
u.
Remove lowering solenoid valve and
clean filter screen.
v. Correct as necessary.
w.
Remove and clean flow control valve.
Refer to Hydraulic System Diagram on p.
14).
x.
Align cylinders correctly.
Page 15 of 20
check the
If
also,
2(f),
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