The services gateway cooling system is a fan tray and an air filter, both of which are located vertically in the rear of the chassis (see Figure 1). The fan tray contains six fans. The fan tray provides cooling to the components installed in the device. Figure 40 shows the airflow through the device.
An air filter installed in the rear of the chassis helps keep dust and other particles from entering the cooling system. To function properly, the entire cooling system requires an unobstructed airflow and proper clearance around the site, as described in Preparing the Site for Services Gateway Installation.
Figure 40: Airflow Through the Chassis
During normal operation, the fans in the fan tray function at less than full speed. The SCB constantly monitors the temperatures detected by sensors and device components, adjusting the speed of the fans as necessary. If the device temperature exceeds the acceptable maximum, the SCB turns off the power supplies. The following conditions automatically cause the fans to run at full speed and also trigger the indicated alarm:
To troubleshoot the fans, follow these guidelines:
If the CLI output lists only one fan failure, and the other fans are functioning normally, the fan is most likely faulty and you need to replace the fan tray, as described in Replacing the Fan Tray.