Bosch rexroth A21VG 10 Series - Testing the hydraulic fluid supply; Performing functional test

Commissioning 41/56
RE 93223-01-B/09.2020, A21VG Series 10, Bosch Rexroth Corporation
system is completely lled and air bled. To inspect, drain the hydraulic uid at
the reservoir port and wait until it drains without bubbles.
8.1.2 Testing the hydraulic uid supply
The axial piston unit must always have a sufcient supply of hydraulic uid. For
this reason, the supply of hydraulic uid must be ensured at the start of the
commissioning process. When you test the hydraulic uid supply, constantly
monitor the noise development and check the hydraulic uid level in the reservoir.
If the axial piston unit becomes louder (cavitation) or the case drain uid is
discharged with bubbles, this is an indication that the axial piston unit is not being
sufciently supplied with hydraulic uid. For information on troubleshooting, see
chapter14 “Troubleshooting” on page 48.
To test the hydraulic uid supply:
1. Allow the diesel engine to run at the lowest speed. The axial piston unit must
be operated without load. Pay attention to leakage and noise.
2. Check the axial piston unit’s reservoir line during the test. The case drain uid
should not contain any bubbles.
3. Increase the load and check whether the operating pressure rises as expected.
4. Carry out 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 (only on the version with boost pump). Refer
to data sheet 93223 for the permissible value.
6. At maximum pressure, check the case drain pressure at port T. Refer to data
sheet 93223 for the permissible value.
8.1.3 Performing functional test
WARNING
Incorrectly connected axial piston unit!
Mixing up the ports will lead to malfunctions (e.g. lift instead of lower) and thus
to corresponding danger to persons and equipment!
▶ Before the functional test, check whether the piping specied in the hydraulic
schematic has been installed.
Once you have tested the hydraulic uid 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 checked
for functional capability 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 diesel engine, check in particular the specied pressures, e.g.
system pressure, boost pressure and case pressure.
▶ If necessary, remove the pressure gauge and plug the ports with threaded
plugs.