APC ACECFR20200SE4 Installation Manual download pdf (Page 11)

5EcoBreeze System Operation and Maintenance

Basic system operation using HACS and a raised floor

• Hot air from the servers is controlled through Hot Aisle Containment Systems (HACS).

• The hot air rises to the ceiling plenum and feeds into the return ducting of the EcoBreeze.

• The IT air is then cooled and returned to the data center through a raised floor plenum or

cold aisle diffusers if a raised floor is not used.

• The cool air is forced through the perforated tiles in front of the server racks and used to

keep the servers at a safe operating temperature.

Basic system operation using RACS and no raised floor

• Hot air from the servers is controlled through ducting connected to the racks.

• The hot air rises to the ceiling plenum and feeds into the return ducting of the EcoBreeze.

• IT air is cooled and returned to the data center through cold aisle diffusers. The diffusers

discharge sends air down the cold aisle.

Condenser coil freeze detection and prevention

The condenser coil is mounted on the top of the Module cabinet and exposed to the elements.

It is potentially subject to partial obstruction as a consequence of snow and ice. The Module

Frame controller detects an obstruction by monitoring the performance of the IEC heat

exchanger on each Module.

When the ambient temperature is below 0°C (32°F) and an obstruction is sensed, the controller

commands the outdoor fan to maximum speed for a period of one minute. If the obstruction is

not cleared, the fan speed is reduced to 50% and the compressor started and operated at a

speed of 50 Hz for a period of six minutes. Additionally, the indoor IT fans are set to maximum

speed during the compressor de-ice operation. The compressor de-ice sequence for a Module

is not exercised more often than once per hour. Should both methods fail to establish normal

power versus speed, an "IEC Performance Degradation Alarm" is asserted by the controller. If

the ambient temperature is above 0°C (32°F) and the controller detects an obstruction, an "IEC

Performance Degradation Alarm" is asserted by the controller immediately.

Door safety interlock

To avoid exposure to moving equipment and sections of the Module that have positive

pressure, the indoor air fan access door and the evaporator coil access door are equipped with

door safety interlock switches. The Module controller monitors the status of the switch. If a

safety interlock opening is detected when the Module is off-line, a warning alarm is generated

for the door opened. If a door is opened during Module operation an alarm is generated and the

fans are stopped. The fans are returned to normal operation after the door has been closed for

five seconds.

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APC ACECFR20200SE4 Installation Manual Page 11