It depends on your AVR/Amp I suppose.Mine is currently set at 27C. Isnt 30C too high? I guess that would depend on your units ability to handle heat, but its not like we have that information.
Even if I drop the trigger to lower than this, the AVR always gets up to 29C while it's switched on.
I suppose that's its operating temperature, so not much point in having the fans on all the time.
Play around with the trigger point and see where yours reaches a stable temp, and then put the trigger at that temp.