rev. 11/1/2016
CB-PMPS, manual.doc
Copyright 2016 Vestil Manufacturing Corp. Page 19 of 23
5
.
"Spongy·
or "Jerky· unit operation.
s
.
Fluid starvation
.
t. Air in system
.
s
.
See 2
(d),
(f)
,
(g), (j)
t
.
See air bleed procedure (p. 19).
6.
Unit lowers too slowly when loaded
.
u. Lowering solenoid valve filter screen
clogged.
v. Pinched tube or hose
.
w
.
Foreign material in flow control valve.
x. Binding cylinders
.
y. Foreign material in velocity fuse.
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.
3)
.
x
.
Align cylinders correctly.
y. Remove and clean velocity fuse. Refer
to Hydraulic System Diagram on p. 3)
.
7
.
Unit lowers too quickly
.
z. Foreign material stuck in flow control
valve.
(In
this case, carriage initially lowers
at a normal rate but accelerates as the
carriage descends).
z. Remove flow control valve from the
valve block and clean. (Refer to Hydraulic
System Diagram on p. 3)
.
8.
Unit raises then lowers slowly.
aa
.
Lowering solenoid valve may be
incorrectly wired or is stuck open
bb. Check valve may be stuck open.
cc. Check for leaking hoses, fittings, pipes
.
dd
.
Cylinder packings may be worn or
damaged
.
aa
.
See 3 (a)
.
bb. Remove and clean check valve
;
(Refer
to Hydraulic Section of Owner's Manual)
.
cc. See 2 (c).
dd
.
Replace packings
(contact
factory for
replacement parts).
9.
Carriage elevates, but does not lower
.
ee. Incorrect lowering solenoid valve
wiring
.
ff
.
Lowering solenoid valve
i
s stuck.
gg. Faulty lowering solenoid coil.
hh. Binding cylinders.
ii. If the carriage lowers too rapidly, air is
present in the hydraulic system causing the
velocity fuse to activate and shut off the oil
flow from the cylinders
. Consequently,
the
deck will not lower.
ee
.
Correct per diagram (p. 8-10)
.
ff
.
Lightly tap down the solenoid coil body
to seat it properly
.
(DO NOT hit coil hard as
it will permanently damage the internal
system
.
DO NOT remove the solenoid
valve from the block because
the
carriage
will descend dangerously quickly.
gg
.
Remove and replace. DO NOT remove
the down solenoid valve fro the block as
the unit will come down at a dangerous
speed.
hh
.
See 4 (c).
ii
.
To unlock, re-pressurize the hydraulic
system.
