The fan in my WD MyBook Duo 16tb does not run

I just purchased a WD MyBook Duo 16tb and set it up, but I noticed that the fan does not run. I could not feel it blow any air, so I turned the unit around and saw that the blades do not turn. I have had it several days now, and the fan has never run. I bought the Duo for photo storage, so I do not use it for video editing or anything truly taxing, but I would think the fan would have come on at some point. Is the fan supposed to run all of the time, or does it only come on when the unit is quite hot? Thanks.

You can run SMART test to check the health of drive using WD Drive Utility. If drive failed in test, recommend to take backup of data immediately.

That test only checks the harddisks, not the enclosure electronics.

I own several My Book Duo enclosures and after experienced the 12 TB and 20 TB Duo models I also have serious doubts about the thermal management.

For the 20TB model after being not in sleep mode for a while, it overheated (orange LED). After letting it cool down and leaving the top cover off it still works, but the drives were too hot to touch.

Another issue is the resonances. This is caused by the top plastic cover, which vibrates due to the drives. Think it is poor design or the fact WD is using Red drives, not Pro or Plus versions.