Avago Technologies 3ware SAS 9750-16i4e - Manual (Page 294)

Chapter 12. Troubleshooting
282 3ware SATA+SAS RAID Controller Card Software User Guide, Version 10.2
Action
The enclosure normally controls the on/off function of the fan. If there is no
over-heating problem, no action is necessary.
8020 Enclosure temp normal
Event Type
Information.
Cause
Applies to 9750 and 9690SA controllers.
The enclosure temperature is now back within the acceptable range.
Action
None required.
8021 Enclosure temp low
Event Type
Information.
Cause
Applies to 9750 and 9690SA controllers.
The enclosure temperature is lower than normal.
Action
In general, cooler operating temperatures are good for enclosure components.
However, if the temperature is very cold, condensation can occur and cause
media errors and damage. Take steps to bring the operating environment back
within the enclosure manufacturer’s specifications.
Allow cold equipment to warm up gradually before powering on.