Juniper QFX5220, Руководство по оборудованию, Страница: 53 / 247

The cooling system in an QFX5220-32CD consists of six fan modules and a single fan in each power supply.
The switch can ordered in one of two airflow directions:
•
Airflow In–Air comes into the switch through the vents in the field-replaceable units (FRUs)
•
Airflow Out–Air comes into the switch through the vents in the port panel.
CAUTION: Airflow In and Airflow Out fans and power supplies cannot be mixed in the
same chassis.
Fan Modules
The fan modules in QFX5220 devices are hot-insertable and hot-removable field-replaceable units (FRUs).
These fan modules are designed for one of the two available airflow directions (Airflow In or Airflow Out).
The fan modules are also color-coded for the airflow direction as well. The fan modules are installed in
the fan module slots on the FRU panel.
The QFX5220-32CD fan modules have six fan modules numbered 0 through 5 when counting from left
to right.
Figure 15 on page 55 shows a fan module.
Figure 15: QFX5220-32CD Fan Module
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You remove and replace a fan module from the FRU end of the chassis. The switch can work with only
five fans. However, we recommend running with all six fans for redundancy and optimal operation of the
switch. If a fan fails, or you want to run the switch without redundancy, leave the sixth fan in place to
maintain proper airflow. When you replace a fan, the switch continues to operate for a limited period of
time (3 minutes) without thermal alarms or shutdown.
The fan modules are available in two product variants that have different airflow directions—FRU-to-port
airflow and port-to-FRU airflow Table 13 on page 56 lists the available fan module product variants and
the direction of airflow in them:
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