M160 Internet Router Hardware Guide
Cooling System Components
The cooling system has the following components. All are hot-removable and
hot-insertable,as described in Field-Replaceable Units (FRUs) on page 4.
Air intake vent,air filter, and intake cover—Providean opening for room air to
enter the router. They are located at the bottom of the chassis front, below the
cable management system,as shown in Figure 1. The air filteris removable
and covers the air intakevent, preventing dust and other particles from
entering the cooling system. For maintenance and replacement instructions,
see “Maintaining the Air Filter” on page 128. The nonremovable air intake
cover is located behindthe air filter and provides EMC shielding.
CAUTION: Do not remove the air filter for more than a few minutes while the
router is operating. Th e fans and impellers are powerful enough to draw in foreign
material, such as bits of wire, through the unfiltered air intake, which could damage
router components.
Front coolingsubsystem—Cools the FPCs, PICs, and midplane. It includes a fan
traylocated behind the cable management system and a large, centralimpeller
behind the craft interface. For replacement instructions, see “Replac ing the Fan
Tray”on page 148 and “Replacing the Front Impeller Assembly”on page 150.
Rear cooling subsystem—Cools the SFMs, host module, PCGs, and power
supplies. It inclu des one impeller located at the upper right of the chassis
rear and another at the lower left, as shownin Figure 2. The upper and
lower impellers are not interchangeable. For replacement instructions, see
“Replacing the Rear LowerImpeller Assembly” on page 154 and “Replacing
the Rear Upper Impeller Assembly” on page156.
Airflow through the Chassis
Figure 20 shows airflow through the chassis and the locat ion of
the impellers and fan tray.
40 Cooling System