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Troubleshooting the M10i Fan Tray

 

Problem:

Description: The fans in the fan tray are not functioning normally.

Solution

To troubleshoot the cooling system:

  1. Check the alarm LEDs on the HCM:
    • If the yellow or red alarm LED on the HCM is lit, issue the show chassis alarms CLI command to view a more detailed description of the alarm cause:

      user@host> show chassis alarms

      For a list of messages that can appear in the output, see Table 1.

    • If all the LEDs on the HCM are not lit, it might indicate that power is not being provided to the router. See Troubleshooting the M10i Power System. In some cases, the Routing Engine shuts down the router by turning off the power supplies if the temperature passes the acceptable maximum.

  2. Check the status of the cooling system by issuing the show chassis environment command. The output includes an entry for each fan and temperature for components, as shown in this example:
    user@host> show chassis environment

    For further description of the output from the command, see the CLI Explorer.

  3. If you receive a temperature alarm:
    • Check the temperature of each component by issuing the show chassis environment command. Temperature sensors on the components detect temperatures above the acceptable range. Verify that the temperature is OK for each component.

    • Check the room temperature.

    • Check the airflow and clearance around the chassis. For the fan tray to function properly, the clearance around the chassis must be sufficient for unobstructed airflow. See Clearance Requirements for Airflow and Hardware Maintenance. For a graphic depiction of the airflow, see M10i Fan Tray Description.

    • Check if a faulty fan is causing the temperature to be elevated for one or more components.

  4. Check the fan tray:
    • Check the status of the fans by issuing the show chassis environment command. Verify that the status is OK and that the fans are Spinning at Normal Speed.

    • If the fan tray fails, determine whether you can distinguish individual blades in a fan—this is not possible when the fans are rotating at normal speed.

  5. If you are unable to correct the problem, replace the fan tray with a spare. For instructions, see Replacing an M10i Fan Tray. If the LED lights correctly on the spare, the original fan tray is faulty. Return it to Juniper Networks for replacement, as described in Returning a Hardware Component to Juniper Networks, Inc..

Table 1: Cooling System Alarm Messages

Chassis Component

Alarm Severity

CLI Message

Alarm Condition

Solution

Fan Trays

Red

fan-name Failure

A fan has failed.

Replace failed fan tray.

Red

Too many fans missing or failing.

Both fan trays are absent from the chassis.

Install missing fan trays.

Yellow

fan-name Removed

A fan is absent.

Install missing fan tray.

Temperature

Yellow

Temperature warm

If the fans are running at full speed and one or more fans have failed, the chassis temperature has exceeded 55° C.

If the fans are running at full speed but no fans have failed, the chassis temperature has exceeded 65° C.

  • Check room temperature.

  • Check air flow.

  • Check fan tray.

 

Red

Temperature hot

If a fan has failed, the chassis temperature has exceeded 65° C. If this condition persists for more than 4 minutes, the router shuts down.

The chassis temperature has exceeded 75° C. If this condition persists for more than 4 minutes, the router shuts down.

  • Check room temperature.

  • Check air flow.

  • Check fan tray.

 

Red

Temperature sensor failure

The temperature sensor has failed.

Contact technical support. SeeContacting Customer Support for more information.