The Red 4Pre, 8Pre, 8Line, and 16Line interfaces contain an internal fan that is low speed and low noise to help prevent over-heating.

Because of this, the fan cannot be turned off and the vents should be left unobstructed. 

The maximum operating ambient temperature for the Red Range of interfaces is 40°C/104°F. 

To help prevent overheating Red interfaces should not be rack-mounted directly above other equipment that may generate significant heat.