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PTX1000 Cooling System


PTX1000 Cooling System Description

Fan Modules

The cooling system in a PTX1000 consists of three 80-W fan modules that operate at 150 cubic feet per minute (CFM) at full speed as well as fans housed in the power supplies. Each fan module has dual counter-rotating fans. Figure 1 shows the fan module for the PTX1000.

Figure 1: PTX1000 Fan Module
PTX1000 Fan Module

The fan modules in a PTX1000 are hot-removable and hot-insertable FRUs. The fan module slots are numbered 0 through 2 from left to right when viewing the chassis from the FRU side (see Figure 2). Each fan module slot has a fan icon and LED next to it.

Figure 2: PTX1000 FRU Panel
PTX1000 FRU Panel
Power supplies (4)
Fan modules (3)

All three fan modules must be installed for optimal operation of the PTX1000. The PTX1000 continues to operate for a limited period of time (30 seconds) during the replacement of the fan module without thermal shutdown.

Airflow Through the Chassis

In the PTX1000 cooling system, cool air enters through the vents in the port panel and hot air exhausts through the FRU panel. This type of airflow is known as airflow out or port-to-FRU airflow. When the chassis is installed, it must be positioned so that the FRUs are next to the hot aisle. Figure 3 shows the airflow through the chassis.

Figure 3: Airflow Through the PTX1000 Chassis (Port-to-FRU)
Airflow Through the PTX1000
Chassis (Port-to-FRU)

Under normal operating conditions, the fan modules operate at a moderate speed. Temperature sensors in the chassis monitor the temperature within the chassis. The system raises an alarm if a fan module fails or if the ambient temperature inside the chassis rises above the acceptable range. If the temperature inside the chassis rises above the threshold temperature, the system shuts down automatically.

PTX1000 Fan Module LEDs

The PTX1000 has status LEDs for each fan module on the left side of the corresponding fan module slot. Figure 4 shows the location of the LED next to the fan module on the PTX1000 FRU panel.


You can check the status of fan modules by using the show system alarms command.

Figure 4: Fan Module LEDs on a PTX1000
Fan Module LEDs on a PTX1000
Status LEDs

Use Table 1 to interpret the state of the fan module LED.

Table 1: PTX1000 Fan Module LED







On steadily

The fan module is operating normally. The system has verified that the module is engaged, and that the fan is operating correctly.


On steadily

An error is detected in the fan module. Replace the fan module as soon as possible. Either the fan has failed or it is seated incorrectly. To maintain proper airflow through the chassis, leave the fan module installed in the chassis until you are ready to replace it.