Particular Notes On Safe Compressor And System Operation; Operation; Regular Tests; Maintenance - Bitzer OSKA9553 Instructions De Service

6.7.8 Particular notes on safe compressor and
system operation
Analysis show that compressor failures are most often
due to an inadmissible operating mode. This applies
especially to damage resulting from lack of lubrication:
• Always maintain oil heater operation in the oil separ-
ator when the system is at standstill. This is valid for
all applications.
When installing the system in zones where the tem-
peratures are low, it may be necessary to insulate
the oil separator. At compressor start, the oil temper-
ature, that is measured under the oil sight glass,
should be 15 .. 20 K above the ambient temperature.
• Automatic sequence change for systems with sev-
eral refrigerating circuits (approximately every 2
hours).
• Install an additional check valve in the discharge gas
line behind the oil separator if temperature and pres-
sure compensation is not reached even after long
standstill times.
• If needed, mount a time and pressure-dependant
controlled pump down system – particularly for high
refrigerant charges and/or when the evaporator may
become hotter than the suction gas line or the com-
pressor.
For further information about pipe layout, see manual
SH-510.

7 Operation

7.1 Regular tests

Examine the system at regular intervals according to
national regulations.
• Operating data, see chapter Checking the operating
data, page 30.
• Oil supply.
• Safety and protection devices and all components
for compressor monitoring, see chapter Safety and
protection devices, page 27 and see chapter Check-
ing the operating data, page 30.
• Tightness of the integrated check valve.
• Check the elastomer elements of the coupling after
the running-in period and then once a year.
• Tight seat of electrical cable connections and
screwed joints.
SB-520-2
• Screw tightening torques, see chapter Tightening
torques for screwed connections, page 33.
• Refrigerant charge.
• Tightness
• Prepare data protocol.

8 Maintenance

DANGER
Hair, hands or clothes may get caught in the
coupling!
Serious injuries are possible.
Secure the coupling zone with a separating
cover (protective grid)!
WARNING
The compressor is under pressure!
Serious injuries are possible.
Depressurize the compressor!
Wear safety goggles!

8.1 Integrated pressure relief valve

The valve is maintenance-free.
However, after repeated venting, it may leak perman-
ently because of abnormal operating conditions. The
consequences are reduced performance and a higher
discharge gas temperature.

8.2 Integrated check valve

If the check valve is defective or contaminated, the
compressor runs for some time in reverse direction
after it has been switched off. The valve must then be
changed.
WARNING
The compressor is under pressure!
Serious injuries are possible.
Depressurize the compressor!
Wear safety goggles!

8.3 Oil filter

It is recommended to change the oil filter for the first
time after 50 .. 100 operating hours.
31