Cisco Network Convergence System 540 Hardware Installation Manual page 23

Prepare for Installation
• Front clearance—5 inches (12.7 centimeters)
• Rear clearance—2 inches (5.08 centimeters)
Figure 3: Airflow Side View for N540-24Q8L2DD-SYS
Note the following points:
• When installing the router in a back-to-back position with another device, ensure that there is a minimum
of 3.9 inches (10 centimeters) airflow clearance between the two devices.
• If airflow through the equipment rack and the routers that occupy it is blocked or restricted, or if the
ambient air being drawn into the rack is too warm, an overtemperature condition may occur within the
rack and the routers that occupy it.
• The site must be as dust-free as possible. Dust tends to clog the router fans, reducing the flow of cooling
air through the equipment rack and the routers that occupy it, thereby increasing the risk of an
overtemperature condition.
• Enclosed racks must have adequate ventilation. Ensure that the rack is not congested because each router
generates heat. An enclosed rack must have louvered sides and a fan to provide cooling air. The equipment
generates heat near the bottom of the rack, which can be drawn upward into the intake ports of the
equipment above.
• When mounting a router in an open rack, ensure that the rack frame does not block the exhaust fans.
• When rack-installed equipment fails, especially equipment in an enclosed rack, try operating the equipment
by itself, if possible. Power off all the other equipment in the rack (and in adjacent racks) to give the
router maximum cooling air and clean power.
• Avoid installing the router in a location in which the router air intake vents may draw in the exhaust air
from adjacent equipment. Consider how the air flows through the router; the airflow direction is front to
back, with ambient air drawn in from the vents located on the sides of the router.
Cisco Network Convergence System 540 Large Density Routers Hardware Installation Guide
Airflow Guidelines
17