Testing The Hydraulic Fluid Supply; Performing A Functional Test - Bosch REXROTH A4 Series Instruction Manual

8.1.2 Testing the hydraulic fluid supply

The axial piston unit must always have a sufficient supply of hydraulic fluid. For
this reason, the supply of hydraulic fluid must be ensured at the start of the
commissioning process.
When you test the hydraulic fluid supply, constantly monitor the noise development
and check the hydraulic fluid level in the reservoir. If the axial piston unit becomes
louder (cavitation) or the drain fluid is discharged with bubbles, this is an indication
that the axial piston unit is not being sufficiently supplied with hydraulic fluid.
For information on troubleshooting, see chapter 14 "Troubleshooting" on page 87.
To test the hydraulic fluid supply:
1. Allow the drive motor to run at the lowest rotational speed. The axial piston unit
must be operated without load. Pay attention to leaks and noises.
2. Check the axial piston unit's drain line during the test. The drain fluid should be
without bubbles.
3. Increase the load and check whether the working pressure rises as expected.
4. Perform a leak test to ensure that the hydraulic system is sealed and can
withstand the maximum pressure.
5. Check the suction pressure at port S of the axial piston pump at nominal speed
and maximum swivel angle. Refer to data sheet 92050 for the permissible value.
6. At maximum pressure, check the leakage pressure at port K
the data sheets in Table 1 "Required and supplementary documentation" on
page 6 for the permissible value.

8.1.3 Performing a functional test

Improperly connected axial piston unit!
Mixing up the ports will cause malfunctions (e.g. lift instead of lower) and could
endanger persons and equipment!
▶ Before the functional test, check whether the piping specified in the hydraulic
circuit diagram has been installed.
Once you have tested the hydraulic fluid supply, you must perform a functional test
on the machine/system. The functional test should be performed according to the
instructions of the machine/system manufacturer.
The axial piston unit is tested for functional capability and performance before
delivery according to the technical data. During commissioning, it must be ensured
that the axial piston unit was installed properly in the machine/system.
▶ After starting the drive motor, check in particular the specified pressures, e.g.,
working pressure and case pressure.
▶ Perform a leak test without and with load prior to normal operation.
▶ If necessary, disconnect the pressure gauge and plug the ports with the specified
threaded plugs.
RE 92076-01-B/10.2017, A4... with HS5E pilot control valve/Series 3x, Bosch Rexroth AG
WARnInG
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, or K . Refer to
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