I recognize this is old but in case someone comes along, a bit of information, the hpe line especially in the g7 and g8 world have a known issue with a few diffrent things causing their fans to run full tilt.
The base of the problem is the way hpe server get their information about fan speed, in the situation that they are used as intended it works perfectly, everything has full data links to ilo on temp reporting and it knows the temp of everything.
Where you have to be careful is using consumer gear that may not have the functions as more expensive enterprise gear, especially hard drives. If the drive doesn’t report its temperature The way ilo likes it will just assume it’s overheated, same with some pci e cards.
This problem goes deeper even with hpe raid controllers and can effect drive transfer speeds.
If your going to deploy on older hp hardware check this document before you buy drives, or be ready to go really deep into firmware modifications to get things working