J2320 And J2350 Cooling System - Juniper J-series Services Router J2320 Getting Started Manual

Chapter 2: System Overview
The AC power supply has a single AC appliance inlet that requires a dedicated AC
power feed. The DC power supply has a terminal block that provides a single DC
input (–48 VDC and return) and requires a dedicated 15 A (–48 VDC) circuit breaker.
The J2350 AC-powered or DC-powered chassis has a power switch and does not
include a power LED.
For information about site power preparations, see "Power Guidelines, Requirements,
and Specifications" on page 105. For information about connecting the router to power
and ground, see "Connecting Power" on page 122.
NOTE: You cannot mix DC and AC power supplies in the same chassis.
WARNING: DC-powered Services Routers are intended for installation only in a
restricted access location.

J2320 and J2350 Cooling System

The cooling system in J2320 and J2350 routers is from side to side. The J2320 router
has five cooling fans and the J2350 router has four cooling fans. The fans draw air
through vents along the left side of the chassis and exhaust it through vents on the
right side of the chassis. The airflow produced by these fans keeps router components
within the acceptable temperature range (see Figure 11 on page 26 and
Figure 12 on page 26). The speed of the fans is adjusted automatically according to
the current temperature.
On J2350 routers that comply with Network Equipment Building System (NEBS)
criteria, an air filter protects the air intake opening at the front of the chassis and
must be replaced periodically. To verify that the system is a NEBS-compliant system,
run the command. A NEBS-compliant system displays the
show chassis hardware
term NEBS in the output. For instructions on how to replace air filters, see "Replacing
Air Filters on J2350 Routers" on page 207.
The Routing Engine monitors the temperature of the router components. If the
maximum temperature specification, as measured at the CPU junction, is exceeded
and the router cannot be adequately cooled, the Routing Engine shuts down the
hardware components.
J2320 and J2350 routers shut down when the CPU temperature reaches 80°C (176°F).
There is no alarm for temperature. You can view the CPU junction temperature using
the command. The CPU temperature runs a few degrees
show chassis routing-engine
higher than the routing engine temperature displayed on the Monitor>Chassis page
of the J-Web interface.
An additional fan is part of each power supply. This fan is not regulated by the
operating system.
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J2320 and J2350 Services Router Hardware Features