Power Supply Airflow and Switch Fan Module Airflow
The power supply module has its own fan for cooling the power supply, and each of the two switch fan
modules has two fans for cooling the switch circuitry. The airflow direction of all three modules must
agree in order to properly cool the installed SSA system. In rack mount configurations the best practice
is to mount all devices with a common cool air side and a common exhaust (hot air) side.
On the SSA switch, two airflow directions are supported:
•
The I/O port side to the power supply side
•
The power supply side to the I/O port side
Note
The power supplies are ordered separately from the switch unit, and you must specify the
airflow direction when you order them. Power supply airflow direction is fixed and cannot be
changed manually. If the ordered power supply has an airflow direction that does not work for
your rack configuration, you must order another power supply that has the correct airflow
direction (see
The SSA switch, as shipped from the factory, is set up for airflow direction from the I/O port side to the
power supply side. If your installation requires that airflow direction be from the power supply side to
the I/O port side, you must reverse the airflow of the switch fan module fans (see
on page 15). Also, you must reverse the rack mount flanges (ears) (see
You can determine airflow direction of the switch fan modules by visually inspecting them for whether a
white label or a fan blade is visible through the fan screen.
Before securing the SSA switch to the rack or installing the power supply into the SSA switch, unpack
the power supply module (see
on page 22) and visually verify that its
airflow direction and that of the switch fan modules agree with the intended configuration as defined in
and
on page 14.
Table 4: Switch Fan Module Airflow Direction
Airflow Direction
Visual Indication
From I/O port side to power supply side
White label is visible on fan unit
From power supply side to I/O port side
Fan blade is visible on fan unit
The power supply airflow direction can also be verified using the power supply manufacturer’s part
number located on the power supply bottom label.
Table 5: Power Supply Airflow Based on Model Number
Model Number
Mfg. Part Number
Airflow Direction
SSA-FB-AC-PS-A
DS460S-3-003
From power supply side to I/O port side
SSA-FB-AC-PS-B
DS460S-3-002
From I/O port side to power supply side
Installation
S-Series Stand Alone (SSA) Switch Hardware Installation Guide
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