Ambient Conditions; Oil-Immersed Applications; Ambient Temperature; Notes On Selecting Hydraulic Fluids - Bosch REXROTH A4 Series Instruction Manual

5.4 Ambient conditions

5.4.1 Oil-immersed applications

Only the HS5 control system is suitable for use in oil-immersed applications.
Using HS5E systems with integrated electronics is not allowed here.

5.4.2 Ambient temperature

The maximum permissible ambient temperature range for HS5E control systems is
-20 °C to +60 °C. It is crucial to pay attention to the information in the valid RE sheet
for the HS5E control system.
We recommend installation in an area with moving ambient air, e.g. in the airflow
of an electric motor.
This applies in particular to the installation location of the integrated on-board
electronics.
Make sure that there is adequate heat dissipation for the electronics.

5.5 notes on selecting hydraulic fluids

The HS5E control system has been designed for the use of hydraulic fluids according
to DIN 51 524 (HL/HLP).
▶ Adhere to all limits specified in the data sheet regarding temperature, viscosity,
cleanliness of the hydraulic fluid.
5.5.2.1 HFC fluids
You are only allowed to use HFCs with HS5E control systems that have the "F" option
(see type code of data sheet 92050). In the case of an application with HFC fluid, be
aware that the service life of the HS5E control system is reduced compared to the
standard application. This is due to the reduced lubricity of the HFC fluid.
There are separately available commissioning regulations for pump systems when
using HFC fluids (RE 92053, amongst others).

5.6 noise development

For design reasons, the axial piston pump generates an increased change in the flow
compared to a vane pump, for example, which results in pressure pulsation. This can
affect fluid noise in addition to airborne and structure-borne noise propagation. In
the final analysis, all of these factors result in an overall picture of "noise".
Frequently, this leads to other components being stimulated too, which creates
noises. This means that when check valves are used, for example, it may be
necessary to adapt the springs that are used to the conditions in the system if
stimulation with noise generation happens.
In the case of the sound pressure level values that are listed in the technical
documentation, the data was determined in an acoustic room. This means that
environmental influences, like the installation location, the overall mechanical
concept, the piping, etc., for example, are not taken into account.
RE 92076-01-B/10.2017, A4... with HS5E pilot control valve/Series 3x, Bosch Rexroth AG
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