I am not sure, but perhaps that could be the rear door "optional
acoustical treatment to reduce the noise emissions from the rack" as
noted in the Site Preparation and Planning Guide:
Part assembly diagrams for 0553, ...:
Since as I recall doors are shipped unattached\unmounted, I doubt
what is described had served to hold things in place behind the door
during shipping. It could be that what is described is instead used to
protect the doors in their off-the-server shipping.
Jones, John (US) wrote:
There's a vertical metal plate with inward-facing foam on the back
door panel of our racks. It covers roughly the center third of the
panel. Anyone have an idea what purpose it serves? Seems to me it
just restricts some airflow. The back of our rack it rather warm &
I'm wondering if the airflow would be better and system temps would
be lower if that panel was removed.
We haven't had any thermal warnings, which implies I'm ok to ignore
it. But it bugs me.