Juniper EX4500 Hardware Manual page 57

NOTE: Only one of the labels, INTAKE or EXHAUST, is visible through the vents of the installed
fan tray.
The color of the label visible through the vents of the installed fan tray must match the color of the ejector
lever on the installed power supply. The color match indicates that the power supply has the correct airflow
for this model. See "AC Power Supply in EX4500 Switches" on page
CAUTION:
visible through the vents of the installed fan tray matches the color of the ejector lever
of the installed power supply. A color match indicates that the direction of airflow
through the fan tray matches the direction of airflow of the power supply.
Temperature sensors in the chassis monitor the temperature within the chassis. The fan tray used in the
switch comes with load-sharing redundancy that can tolerate a single fan failure at room temperature
(below 113° F/45° C) to still provide sufficient cooling.
Under normal operating conditions, the fans in the fan tray run at less than full speed. If a fan fails or the
ambient temperature rises above the threshold 113° F (45° C), the speed of the remaining fans is
automatically adjusted to keep the temperature within the acceptable range, 32° F (0° C) through 113° F
(45° C).
The system raises an alarm if the fan 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.
You can check the status of fans and the chassis temperature from the Environment Status option in the
Status menu on the LCD panel. See
You cannot replace a single fan. If one or more fans fail, you must replace the entire fan tray.
RELATED DOCUMENTATION
Clearance Requirements for Airflow and Hardware Maintenance for EX4500 Switches | 81
To prevent overheating of the chassis, verify that the color of the label
"LCD Panel in EX4500 Switches" on page
58.
38.
57