On the iDRAC, there are some configurations related to the optional security bezel with dust filter.
Under Countdown Mode, the filter change interval can be manually set:
While the Active Sensing Mode is set, iDRAC is monitoring the filter pressure sensor to determine the filter status. The filter check interval can be manually set.
When the scheduled active filter checking occurs, system fans run at full speed to get a viable airflow reading.
When a dust filter starts to report alert events, it must be replaced. It is possible to contact Dell sales to purchase a Filter Customer Kit.
Starting from iDRAC version 7.00.60.00, if the filter is set as Active Sensing Mode. After a new filter is installed, it is necessary to click on Reset AirFilter Life in the iDRAC UI to manually reset and update the baseline threshold.
NOTE: This Reset AirFilter Life action must only be taken when a clean new filter is installed under Active Sensing Mode.