Cisco Systems 4900 Series manual Chassis Cooling, Fan

Chapter 1 Product Overview

		Switch Components
Table 1-1	LED Functions (continued)
LED	Color or State	Description
FAN	Off	No power to the switch or fans (the tray may
		not be plugged in especially if one or more of
		the power supplies status LED is green)
	Green	Fan tray operational
	Red	Fault detected
PS1 and	Off	No power to the PS
PS2	Green	Operational1
	Red	Fault detected or the on/off switch is set to
		off while the power supply is plugged in

1.If either LED is green and the other is OFF the power supply is probably not plugged in. If it is red, the supply is either plugged in and not switched on or it is faulty. It may be necessary to use the CLI for further status information.

Chassis Cooling

Note For environmental specifications, see Chapter 2, “Site Planning.”

The hot-swappable system fan tray provides cooling air for the internal chassis components. The fans exhaust air to the rear, and fresh air is drawn in from the sides of the chassis.

Caution When the fan tray is removed, internal circuitry is exposed that should not be touched by tools or fingers. The system should not be left operating without a fan tray for longer than is necessary to replace a faulty fan tray with a new one.

Figure 1-8shows the direction of airflow going in and out of the switch.

	Catalyst 4900 Series Switch Installation Guide
78-18039-02		1-11