Troubleshooting 93/104
RE 92076-01-B/10.2017, A4... with HS5E pilot control valve/Series 3x,
Bosch Rexroth AG
Table 27: Malfunction table of HS5E control systems
Malfunction
Possible cause
Remedy
Screaming noise
Oil level in the reservoir too low; pump partly
aspires air
Top up oil
Pump draws in air
Change routing of the suction line
Suction line leaky
Seal suction line
Pump cavitates when pressure is reduced
Diagnosis: Measure, whether the pressure in the
pressure line overshoots
Optimize controller, reduce the command
value via a ramp or in steps
Fluid in the reservoir is mixed with air; cooling
and/or filtration circuit leaky
Seal
Other unusual noise
Drive speed too high
Machine or system manufacturer
Wrong direction of rotation
Machine or system manufacturer
Inadequate suction conditions, e.g. air in the
suction line, insufficient diameter of the suction
line, viscosity of the hydraulic fluid too high,
suction height too high, suction pressure too low,
foreign particles in the suction line
Check whether shut-off valves are open
Machine or system manufacturer (e.g. optimize
inlet conditions, use suitable hydraulic fluid)
Completely air bleed the control system, fill
suction line with hydraulic fluid
Remove foreign particles from the suction line
Incorrect mounting of the control system
Check mounting of the control system according
to the specifications of the machine or system
manufacturer. Observe tightening torques
Incorrect mounting of the assembled parts,
e.g. coupling and hydraulic lines
Mount assembled parts according to the
information provided by the coupling or fitting
manufacturer
Air in the pump or in the preload valve
Bleed pump and preload valve
Wear/mechanical damage to the control system
Replace the control system, contact Rexroth
Service
No or insufficient pressure
(< 4 bar)
Faulty mechanical drive (for example, defective
coupling)
Machine or system manufacturer
Hydraulic fluid not in optimum viscosity range
Use suitable hydraulic fluid (machine or system
manufacturer)
Output unit defective (e.g. hydraulic motor
or cylinder)
Machine or system manufacturer
Wear/mechanical damage
Replace the control system, contact Rexroth
Service
Pressure statically at approx
5...12 bar, cannot be changed
Supply voltage not within the permissible range
Diagnosis: Check the status LEDs
Check, whether central plug XH4 is connected
to the pilot valve
Check voltage at the last interconnection point
(terminal strip) upstream of the pilot valve
Command value for pressure, swivel angle or
power (optional) is 0 bar or 0%, respectively
If you use, for example, exclusively closed-
loop pressure control, provide a swivel angle
command value of 100%
Swivel angle sensor defective
Check swivel angle measurement, see
Chapter 8.1.5.4 on page 69
Spool jams in pilot valve
Contact Rexroth Service