Table of Contents
Pressure Valves
Flow Control Valves
1.Valve chatter due
1.The valve
to dirt on valve seal
oscillates and
2.Insufficient
excites other control
damping (unsuitable
elements into
flow)
oscillation
3.Flow noises when
2.Flow noises
operating
3.Control system
4.Unsuitable
oscillating
characteristic curve
5.Wrong design
1.Operating
1.Pressure losses
pressure set too low
excessive
2.Internal leakage
2.False setting
due to wear
3.Valve defective
3.Dirty or damaged
4.Unsuitable type
valve seat
4.Broken spring
5.Unsuitable type.
(setting too low)
1.Valve chatter due
1.Valve dirty
to dirt on valve seat
2.Pressure losses
or valve worn
excessive
2.Insufficient
damping (unsuitable
type)
3.Excessive length
of undamped
remote control line
4.Unsuitable remote-
control valve
Causes Of Trouble And Its Effect In The Hydraulic Installation
Directional Control
Valves
1.Valve chatters due
to defective solenoid
or the voltage is too
low
2.Valve defective
due to dirt or wear
3.Flow through valve
is excessive
4.Pilot pressure
variations
5.On valves with
adjustable damping
the adjustment has
not been performed
6.Check the
electrical controls
1.Wrong switched
position (eg
pressureless)
2.Solenoid defective
3.Internal leakage
due to wear
4.Excessive fluid
velocity
5.Spool jams
1.Valve chatters due
to defective solenoid
or the voltage is too
low
2.Valve defective
due to dirt or wear
3.Flow through valve
is excessive
4.Pilot pressure
variations
5. Adjustable
damping on valves,
has not been set
6.Check the
electrical controls.
Hägglunds DOb, RE 15327-WA/05.2017, Installation and maintenance manual, Bosch Rexroth AB
output Drive
Fluid
(motor)
1.Cavitation
1.Wear of running
problems due to
surfaces
low fluid level or
2.Control system
viscosity too high.
oscillating
(fluid temperature is
too low)
2.Fluid is
contaminated
and dirty leading
to damage and
blockage of
equipment
3.Fluid foams
1.Viscosity too low,
1.Internal Leakage
causing excessive
2.Wear or running
leakage.
surfaces
2.Viscosity too high
3.Excessive internal
causing excessive
friction causing low
flow resistance
efficiency
3.Fluid foams.
1.Hydraulic fluid
1.Stick-slip effect
dirty
due to friction
2.Hydraulic fluid
2.Operation
foams.
below minimum
recommended
motor speed.
1. Unsuitable fluid
for the duty.
Troubleshooting
73/80
others
1.In the case of
pressure controls
there is a defect in
the open (or closed)
loop control circuit
2.Display
instruments are
defective
1.Insufficient load
counter-balance (eg
lowering control
valve)
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