Juniper MX2010 Hardware Manual page 644

(0 and 1). Zone 1 consists of the CB-REs and SFBs located in the upper portion of the chassis. Zone 1 is
cooled by fan trays 2 and 3. Two fan trays are at the bottom of the chassis, and two fan trays are at the
top of the chassis.
Action
On a regular basis:
Check the LEDs on the craft interface for upper and lower fan trays. The green status LEDs labeled 0
and 1, for lower fan trays, and 2 and 3 for the upper fan trays light steadily when a fan tray is functioning
normally.
Place your hand near the exhaust vents at the rear of the chassis to determine whether the fans are
pushing air out of the chassis.
Monitor the status of the fans. During normal operation, the fans in each fan tray function at less than
full speed.
The fan trays each contain multiple fans that work in unison to cool the router components. If one fan
fails, the host subsystem adjusts the speed of the remaining fans to maintain proper cooling. A red alarm
is triggered when a fan fails, and a yellow alarm is triggered when a fan tray is removed.
During normal operation:
The green LEDs next to the fan trays 0, 1, 2, and 3 on the craft interface light steadily when the fan tray
is functioning normally for that zone.
Issue the show chassis zones command to check the status of the two cooling zones. The output is
similar to the following:
user@host> show chassis zones
ZONE 0 Status
Driving FRU
Temperature
Condition
Num Fans Missing
Num Fans Failed
Fan Duty Cycle
ZONE 1 Status
Driving FRU
Temperature
Condition
Num Fans Missing
Num Fans Failed
ADC 6 Exhaust
63 degrees C / 145 degrees F
HIGH TEMP
0
0
27
SFB 7 Exhaust-Zone1
64 degrees C / 147 degrees F
WARM TEMP
0
0
628