Juniper EX4400 - Page 207

If the switch is operaonal while you are replacing fan modules, you must remove only one fan
module at a me. The switch connues to operate for 60 seconds without thermal shutdown while
you are replacing a fan module.
Install a Fan Module in an EX4400 Switch
Before you install a fan module in the switch:
• Ensure that you understand how to prevent electrostac discharge (ESD) damage (see Prevenon of
Electrostac Discharge Damage ).
• Ensure that you have the correct fan module. If the label on the installed power supply is AIR IN, you
must install a fan module with the label AIR IN. If the label on the installed power supply is AIR OUT,
you must install a fan module with the label AIR OUT.
• Ensure that you have the following parts and tools available:
• Number 2 Phillips (+) screwdriver—not provided
• An ESD grounding strap—not provided
We ship EX4400 switches with 1+1 redundant fan modules preinstalled in the rear panel. The fan
modules in EX4400 switches are hot-removable and hot-insertable eld-replaceable unit (FRU) installed
in the rear panel of the switch: You can remove and replace them without powering o the switch or
disrupng switch funcons.
CAUTION: Do not mix:
• Fan modules with dierent airow direcons in the same chassis.
• Power supplies and fan modules with dierent airow direcons in the same chassis.
If you install power supplies or fan modules with dierent airow direcons, Junos OS
raises an alarm.
To install a fan module:
1. Wrap and fasten one end of the ESD wrist strap around your bare wrist, and connect the other end
of the strap to a site ESD point.
2. Remove the fan module from its bag.
3. Hold the handle of the fan module with one hand and support the weight of the module with the
other hand. Place the fan module in the fan module slot on the rear panel of the switch and slide it in
unl it is fully seated.
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