Table 100: Mx2020 Cooling System Alarms - Juniper MX2020 Hardware Manual

Solution
Copyright © 2015, Juniper Networks, Inc.
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

Table 100: MX2020 Cooling System Alarms

Alarm
Component Type
Fans Red
Chapter 27: Troubleshooting Components
Table 100 on page
CLI Message Alarm Condition
fan-nameFailure A fan has failed.
user@host>show
535.
Solution
Replace the fan
tray.
535