Fan Modules - Juniper EX4300 Series Hardware Manual

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Fan Modules

In the EX4300 switches the fan modules are hot-insertable and hot-removable field-replaceable units
(FRUs).
All the EX4300 switches, except EX4300-24T-S, EX4300-24P-S, EX4300-32F-S, EX4300-48T-S, and
EX4300-48P-S switches are shipped with two fan modules pre-installed in the rear panel of the switch.
EX4300-24T-S, EX4300-24P-S, EX4300-32F-S, EX4300-48T-S, and EX4300-48P-S switches are not
shipped with pre-installed fan modules; you must order them separately. Each switch can accommodate
two fan modules in the fan module slots on the rear panel of the switch. The fan module slots are
numbered 0 and 1 and each slot has a fan icon next to it.
Figure 38 on page 83 shows the fan module used in an EX4300 switch:
Figure 38: Fan Module Used in an EX4300 Switch
You must remove only one fan module at a time for replacement from the rear panel of the chassis. The
switch continues to operate for a limited period of time (30 seconds) during the replacement of the fan
module without thermal shutdown.
NOTE: Both the fan modules must be installed for optimal functioning of the switch.
The fan modules are available in two models that have different airflow directions—back-to-front (air
enters through the back of the switch), indicated by label AIR IN (AFI), and front-to-back (air exhausts
through the back of the switch), indicated by label AIR OUT (AFO). Table 27 on page 84 lists the
available fan module models and the direction of airflow in them.