Reference Manual

Unit Description, RBS 2106 Climate Unit
Active Cooler
The liquid cooling media passes through a reducing valve, where it
evaporates to a cold low-pressure gas. This gas flows through the
evaporator and cools it. The inside air that has passed the heat
exchanger is blown through the evaporator, cooled and returned to the
cabinet subracks.
The compressor compresses the cooling media to a liquid state again in
the condenser. The cooling media and the condenser becomes hot in the
process. An AC-powered fan circulates the outside air through the
condenser and cools it.
When the temperature exceeds the compressor start point, the CCU
supplies mains voltage, first to the condenser fan and then to the
compressor. The condenser fan will run when the compressor is
running and one minute after the compressor is switched off.
The compressor cannot start again before the condenser fan has
stopped. This is done to equalise the pressure differences in the cooling
system before the compressor starts.
When the temperature decreases below the compressor stop value, a
compressor stop signal is activated, but the compressor will continue
running for at least 10 minutes.
If the return air temperature should drop to +15

, the compressor is
stopped immediately to prevent the risk that the heater and active
cooling should operate simultaneously.
If the mains current to the compressor is missing, it is reported as
compressor failure.
The condenser fan is provided with a rotation signal output. If the
signal is missing, an active cooler fan alarm is reported.
Heater
The heater is powered by mains voltage, and heats the inside air if the
start-up temperature inside the cabinet is below +5

. The heater has a
capacity of 2 kW.
The CCU measures the return air temperature and controls the heater.
Climate Control Unit (CCU)
The CCU provides the following main functions:
• Monitoring of internal and external temperatures
• Monitoring and control of the internal and external fans
• Monitoring and control of the compressor
• Monitoring and control of the condenser fan
• Monitoring and control of the heater
• Alarm handling
• Mains voltage supervision
• Test
218 (485)
EN/LZT 720 0008 P2A
2001-11-28
© Ericsson Radio Systems AB
— All Rights Reserved —
Preliminary