Setting High Pressure And Low Pressure Switches (Hp + Lp); Setting The Condenser Pressure Control; Checking The Operating Data; Vibrations - Biber OSKA9563 Instructions De Service

NOTICE
!
!
Risk of wet operation during liquid feeding!
Measure out extremely precise quantities!
Maintain the discharge gas temperature well
above the condensing temperature:
with NH at least 30 K.
3
If the oil level switch is triggered during the start phase
of the oil monitoring system or after the delay time has
elapsed (10 s), this indicates an acute lack of oil. This
may be caused by a too large share of refrigerant in the
oil. Check the suction gas superheat.
NOTICE
!
!
Risk of compressor failure due to liquid slug-
ging!
Before adding larger quantities of oil: check the
oil return!
6.7.4 Setting high pressure and low pressure
switches (HP + LP)
Perform a test to check the exact cut-in and cut-out
pressure values according to the application limits.
6.7.5

Setting the condenser pressure control

Set the condenser pressure so that the minimum pres-
sure difference is reached within 20 s after the start (for
application limits, see BITZER SOFTWARE). Avoid
quick pressure reduction with finely stepped pressure
control.
6.7.6

Checking the operating data

• Evaporation temperature
• Suction gas temperature
• Condensing temperature
• Discharge gas temperature:
– Min. 30 K (NH ) above condensing temperature
3
– Max. 100°C
• Oil temperature:
– Reniso KC68, Reflo 68A, SHC226E: max. 60°C
• Cycling rate
• Motor current
• Motor voltage
• For operation with ECO:
– ECO pressure
– Temperature at the ECO connection
12
• Creation of data protocol
For application limits, see brochure SP-520 or
BITZER SOFTWARE.
To prevent motor failures, the following requirements
are specified:
• Maximum cycling rate, motor current, motor voltage:
Observe the notes of the motor manufacturer.
• Desirable minimum running time: 5 min
NOTICE
!
!
Risk of motor failure!
The specified requirements must be ensured by
the control logic!
6.7.7

Vibrations

When operating with frequency inverter, check the en-
tire speed range of the system for abnormal vibration.
Speeds at which resonances still occur must be
avoided in the programming of the frequency inverter. If
required, take additional safety measures.
NOTICE
!
!
Risk of burst pipes and leakages on the com-
pressor and system components!
Avoid strong vibrations!
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
SB-520-1