FAN RPM is always 0 (My Cloud Mirror 4TB)

My Cloud OS 3 Personal & Network Attached Storage My Cloud Mirror
2

i think it’s the same problem with ex2

http://community.wd.com/t5/WD-My-Cloud-EX2/Question-regarding-the-FAN-used-by-WD-My-Cloud-EX2/td-p/771843

looks like the fan only kicks in around 60C