User Manual

Cabinet descriptionNortel Networks Confidential 1–9
S8000/S8002/S8006 BTS Reference Manual
Normal temperature Tcab = 40°C (104°F)
The damper position is controlled automatically by the modulating motor,
mixing appropriate amounts of recirculated and external air to maintain a
constant temperature. Excess air is rejected from the cooling system from vents
either side of the cooling system.
High temperature Tcab > 40°C (104°F)
Although the damper is fully open, the cooling system is unable to keep the
cabinet temperature to 40°C (104°F) which now rises in sympathy with the
external temperature. At an outside temperature of 50°C (122°F), the internal
cabinet will rise to a nominal 60°C (140°F) under fully loaded conditions.
The cooling system is supplied:
with two hard alarm outputs:
• The first alarm output signals a fault on the cooling system,
• The second one indicates a maintenance requirement for the filter.
three alarm LEDs for on–site fault diagnostics:
• The red LED indicates critical alarm for fan failure.
• The yellow LED indicates critical alarm for heater circuit failure.
• The green LED indicates maintenance alarm for clogged filter.
On the top of the cooling system, there is a window in the lid which allows to
view the LEDs (see Figure 1–4). They are normally on when healthy and off on
alarm.
The cooling system is DC powered that allows internal or external battery back–up.
The dc power consumption of the cooling system is 400–450W. The cold start–up
performance of the unit is controlled by an inbuilt ac to dc converter (for operation
of the fans) and by a 2.5 kW heating element.
With “LN” (Loise Noise) DACS
Figure 1–6 shows the S8000 Outdoor with an ”LN” DACS climatic system.
The operating principle is the following:
The air damper opens to admit external air (incoming air being filtered) and
controls the inner cabinet environment by mixing appropriate amounts of outside
and recirculated air.
The twin blowers drive air down the rear duct and into the equipment enclosure
via slots at the rear. Returned air to the cooling system is routed through two sets
of holes in the base, with excess air being rejected from vents either located on
either side of the system (see Figure 1–5).