Positioning The Switch; Fan Module Status - Juniper EX4300 Series Hardware Manual

The labels on the power supplies and fan modules should match the labels on the switch chassis.
Mixing components with AIR IN (AFI) and AIR OUT (AFO) labels in the same chassis hampers the
performance of the cooling system of the switch and leads to overheating of the chassis.
CAUTION: The system raises an alarm if a fan module fails or if the ambient
temperature inside the chassis rises above the acceptable range. If the temperature
inside the chassis rises above the threshold temperature, the system shuts down
automatically.

Positioning the Switch

In front-to-back airflow, indicated by the label AIR OUT (AFO) on the fan modules and power supplies,
hot air exhausts through the vents on the rear panel of the switch. In back-to-front airflow, indicated by
the label AIR IN (AFI) on the fan modules and power supplies, hot air exhausts through the vents on the
front panel of the switch.
In data center deployments, position the switch in such a manner that the AIR IN (AFI) labels on switch
components are next to the cold aisle, and AIR OUT (AFO) labels on switch components are next to the
hot aisle.

Fan Module Status

Each switch has a status LED for each fan module next to the fan module slot on the rear panel of the
chassis. The Status LED indicates the status of the fan module.
Status LED on the fan module in an EX4300 switch.
Table 29: Fan Module Status LED
LED State
Status Green
Table 29 on page 89
Description
The fan module is functioning normally.
describes the
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