Hi eugene1973,
Have you ventured into investigating this from a more, troubleshooting point of view?
Meaning, do you see any logs in chassisd or alarms indicating that the FANs are infact now at intermediate speeds or at higher speeds, etc ?
Also, 'show chassis temperature-thresholds' will show you the expected Fan behavior over a range of temperatures. And 'show chassis environment' will cover the present/current temperature situation on your chassis.
Perhaps finding out if the Fan is behaving as expected, would be a place to start?
Cheers
Pooja
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