Cisco Systems 9001, 9001S, ASR9001, ASR9001s Troubleshooting the Cooling Subsystem

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Cisco ASR 9001 and Cisco ASR 9001-S Routers Hardware Installation Guide
OL-26701-02
Chapter 4 Troubleshooting the Installation
Troubleshooting the Cooling Subsystem
Note It is important to collect the show tech-support command data before doing a reload or power cycle.
Failure to do so can cause all information about the problem to be lost. Output from these commands
varies slightly depending on which line card you are using, but the basic information is the same.
Troubleshooting the Cooling Subsystem
You may need to troubleshoot the cooling subsystem if an over-temperature condition occurs. The
cooling subsystem of the router consists of a fan tray in the chassis and a fan in each of the power
supplies. The fan tray and the power supply fans circulate air to maintain acceptable operating
temperatures within the router.
This section contains information to troubleshooting the cooling subsystem and includes:
•Fan Tray Operation, page 4-18
•Power Module Fans, page 4-18
•Over-temperature Conditions, page 4-19
•Isolating Cooling Subsystem Problems, page 4-19
Fan Tray Operation
The fan tray maintains acceptable operating temperatures for the internal components by drawing
cooling air into the system chassis. The fan tray receives power from the chassis backplane.
The fan tray contains 14 fans, a controller card, and one front panel STATUS LED indicator:
•Green—Fan tray is functioning properly.
•Red—There is a fault detected in the fan tray.
If the air temperature inside the chassis rises, blower speed increases to provide additional cooling air to
the internal components. If the internal air temperature continues to rise beyond the specified threshold,
the system environmental monitor shuts down all internal power to prevent equipment damage because
of excessive heat.
If the system detects that one or more of the fans in the fan tray has failed, it displays a warning message
on the system console. In addition, the remaining fans go to full speed to compensate for the loss of the
failed fan.
Power Module Fans
Each AC or DC power module is equipped with one fan that draws cooling air in through the front of the
power module and force warm air out through the air exhaust of the chassis:
•If the power source is within the required voltage range, the power supply fan remains on.
•If a fan fails:
– Power module detects an internal over-temperature condition.
– Fault and Temp indicators light.
– Power module sends an over-temperature warning to the system and then power supply
switchover to the redundant power module.