Troubleshooting The Mx2020 Cooling System - Juniper MX2020 Hardware Manual

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Troubleshooting the MX2020 Cooling System

Problem
Solution
Copyright © 2013, Juniper Networks, Inc.
Use the CLI to check the alarms.
3.
Standalone MX2020 router—Issue the
alarms.
MX2020 Host Subsystem Description on page 25
MX2020 Craft Interface Description on page 33
The following alarms, LEDs, and other conditions indicate a problem with the cooling
system:
A red alarm indicates that temperature of the router exceeds the maximum
("temperature hot") threshold.
Automatic shutdown of the power system was caused by the temperature of the router
exceeding the maximum ("temperature hot") threshold.
A red alarm indicates that a fan failed.
A yellow alarm indicates that the router temperature exceeds the "temperature warm"
threshold.
A yellow alarm indicates that one of the fan trays was removed.
One or more fans in a fan tray function at full speed. The CB-RE constantly monitor
the temperatures detected by sensors on the midplane and router components,
adjusting the speed of the fans as necessary.
To troubleshoot the cooling system:
Place your hand near the exhaust vents at the back of the chassis to determine whether
1.
the fans are pushing air out of the chassis.
If the red alarm LED on the craft interface lights, look at the craft interface display to
2.
find the source of the problem. The number of alarm conditions, as well as the source
of each alarm, appears on the screen.
If the craft interface display lists only one fan failure and the other fans are functioning
3.
normally, the fan is probably faulty and you need to replace the fan tray.
Use the CLI to check the status of the fans. For example, you can issue the following
4.
command to get information about the source of an alarm condition:
chassis alarms
For information about the alarms, (see
Chapter 12: Troubleshooting MX2020 Router Hardware Components
show chassis alarms
Table 38 on page
command to view the
user@host>show
198).
197