Juniper MX204 Hardware Manual page 120

For optimum cooling, verify the condition of the fans.
Action
Monitor the status of the fans. A fan module contains multiple fans that work in unison to cool the router
components. If one fan fails, the router adjusts the speed of the remaining fans to maintain proper
cooling. A red alarm is triggered when a fan fails, and a yellow alarm and a red alarm are triggered when
a fan module is removed.
To display the status of the cooling system, issue the show chassis environment command. The output
is similar to the following:
user@host> show chassis environment
Class Item
Temp CB 0 Top Right Inlet Sensor
CB 0 Top Left Inlet Sensor
CB 0 Top Right Exhaust Sensor
CB 0 Top Left Exhaust Sensor
CB 0 CPU Core-0 Temp
CB 0 CPU Core-1 Temp
CB 0 CPU Core-2 Temp
CB 0 CPU Core-3 Temp
CB 0 CPU Core-4 Temp
CB 0 CPU Core-5 Temp
CB 0 CPU Core-6 Temp
CB 0 CPU Core-7 Temp
FPC 0 EA0_HMC0 Logic die
FPC 0 EA0_HMC0 DRAM botm
FPC 0 EA0_HMC1 Logic die
FPC 0 EA0_HMC1 DRAM botm
FPC 0 EA0 Chip
FPC 0 EA0-XR0 Chip
FPC 0 EA0-XR1 Chip
Power PEM 0
PEM 1
Fans Fan Tray 0 Fan 0
Fan Tray 0 Fan 1
Fan Tray 1 Fan 0
Fan Tray 1 Fan 1
Fan Tray 2 Fan 0
Fan Tray 2 Fan 1
SEE ALSO
Status Measurement
OK 35 degrees C / 95 degrees F
OK 38 degrees C / 100 degrees F
OK 45 degrees C / 113 degrees F
OK 64 degrees C / 147 degrees F
OK 49 degrees C / 120 degrees F
OK 49 degrees C / 120 degrees F
OK 48 degrees C / 118 degrees F
OK 49 degrees C / 120 degrees F
OK 49 degrees C / 120 degrees F
OK 48 degrees C / 118 degrees F
OK 48 degrees C / 118 degrees F
OK 48 degrees C / 118 degrees F
OK 81 degrees C / 177 degrees F
OK 78 degrees C / 172 degrees F
OK 85 degrees C / 185 degrees F
OK 82 degrees C / 179 degrees F
OK 93 degrees C / 199 degrees F
OK 69 degrees C / 156 degrees F
OK 73 degrees C / 163 degrees F
ok
OK 49 degrees C / 120 degrees F
OK Spinning at normal speed
OK Spinning at normal speed
OK Spinning at normal speed
OK Spinning at normal speed
OK Spinning at normal speed
OK Spinning at normal speed
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