D-Link DSN-3400-10 - xStack Storage Area Network Array Hard Drive Hardware Reference Manual page 40

3. Remove the fan from its socket as seen in Figure A-18.
Figure A-18 Remove the Fan
4. Insert the new fan by reversing the previous steps. i.e. Insert fan into socket, press
firmly downwards until it is seated and lower the handle to lock it in place.
40 Appendix A Replacing and Upgrading FRUs