HP ProLiant DL180 Gen9 User Manual page 77

Position the heatsink on the processor backplate.
a.
Tighten one pair of diagonally opposite screws halfway, and then tighten the other pair of screws.
b.
Finish the installation by completely tightening the screws in the same sequence.
c.
To determine which fan blanks need to be removed to install the additional fans, see "Fan population
14.
guidelines (on page 79)."
Remove the fan blank.
15.
Install the fan.
16.
Hardware options installation 77