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SYDFED-2X, SYDFED-3X, SYHDFED-1X
| Troubleshooting
Bosch Rexroth AG, Edition 11.2021, RE 30017-B
Table 28: Fault table of SY(H)DFED control systems
Malfunction
Possible cause
Remedy
Other unusual noise
Input speed too high
Machine or system manufacturer
Wrong direction of rotation
Machine or system manufacturer
Insufficient 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 great, suction pressure
too low, foreign body in the suction line
Check, whether shut-off valves are open
Machine or system manufacturer (e.g.
optimize inlet conditions, use suitable
hydraulic fluid)
Air-bleed control system completely, fill
suction line with hydraulic fluid
Remove foreign particles from the suction
line
Improper mounting of the control system
Check mounting of the control system
according to the instructions given by the
machine or system manufacturer. Observe
tightening torques
Improper mounting of attachment parts, e.g.
coupling and hydraulic lines
Mount attachments in accordance with
the instructions of the coupling or fitting
manufacturer
Air in the pump or in the pre-load valve
Bleed pump and pre-load valve
Wear/mechanical damage to the control system Replace control system, contact Rexroth
Service
No or insufficient pressure
(< 4 bar)
Faulty mechanical drive (e.g. defective
coupling)
Machine or system manufacturer
Hydraulic fluid not within the optimum
viscosity range
Use suitable hydraulic fluid (machine or
system manufacturer)
Drive unit defective (e.g. hydraulic motor or
cylinder)
Machine or system manufacturer
Wear/mechanical damage
Replace control system, contact Rexroth
Service
Pressure fixed, ca. 5...12 bar,
cannot be changed
Supply voltage not within the permissible
range
Diagnostics: Check 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
Spool jams in pilot valve
Contact Rexroth Service