Late 2012 iMac fan randomly kicks on hard

[Nautilus007]

My late 2012 iMac is usually left on nothing running except maybe iTunes and reeder and like every 30-40 minutes the fans kick on for like 30-40 seconds at high speeds. Anybody know a solution? The computer is brand new.

 

[Nautilus007]

and i can always hear the fan slightly when the machine is on.

 

[Nautilus007]

I am pretty sure the noise is actually my fusion drive after fooling with smcfancontrol. It is coming from the left side.