Cisco ESW2 Series Quick Start Manual page 5

(Optional) To reverse the air flow on the switch, rotate the fan
S 3
TEP
module 180 degrees.
Place the fan module back into the fan tray by lining it up with the
S 4
TEP
guides and pushing straight down. You should hear an audible click
when it is in place.
Cisco ESW2 Series Advanced Switches 5