Bosch A4VG A4VG 32 Series Instruction Manual page 64

64/68 Troubleshooting
Table 13: Axial piston unit malfunction table
Malfunction
Pressure/flow fluctuations
or instabilities
Excessive hydraulic fluid
temperature and housing
temperature
Bosch Rexroth AG, A4VG Series 32, RE 92003-01-B/12.2015
Possible cause
Insufficient air bleeding of the hydraulic system
Insufficient suction conditions, e.g. insufficient
dimensioning of the suction line, viscosity of
the hydraulic fluid too high, suction height too
high, suction pressure too low, contaminants in
the suction line, suction filter too small, etc.
Oscillate pressure limitation and pressure
control valves of the axial piston unit (boost
pressure-relief valve, high-pressure relief
valve,pressure cut-off)
Unstable control signal
Malfunction in the control devices or the
controller
Excessive inlet temperature in the axial piston
unit
Wrong setting or malfunction in the pressure
relief and pressure control valves (e.g., high-
pressure relief valve, pressure cut-off,
pressure controller)
Flushing flow of the flushing valve too low
Axial piston unit worn
Remedy
Fill axial piston unit, suction line for
the hydraulic pump and the reservoir
Completely air bleed axial piston unit
and hydraulic system
Check correct installation position
Machine/system manufacturer: check
the system, e.g. optimize inlet conditions,
use suitable hydraulic fluid
Fill the suction line with hydraulic fluid
Remove contaminants from the suction line
Check the filter system and change the
filter as necessary
Air bleed axial piston unit and hydraulic system
Contact Bosch Rexroth Service
Contact machine/system manufacturer or
Bosch Rexroth Service
Contact Bosch Rexroth Service
Machine/system manufacturer: inspect system,
e.g., malfunction in the cooler, insufficient
hydraulic fluid in the reservoir
Optimize the adjustment of the pressure
limitation and pressure control valves of the
axial piston unit and the pressure safeguarding
in the hydraulic system
Contact Bosch Rexroth Service
Contact machine/system manufacturer
Contact Bosch Rexroth Service
Replace axial piston unit, contact
Bosch Rexroth Service