I think if you push and hold the right button for a second your two it will change. If you just push quickly and let go it will change to clock. Once on clock if you hold it for a few seconds it will start blinking so you can ajust the clock, so I think if you just hold it while it is on temp for a few seconds it will switch between F and C. Not 100% on that.
Fans are supposed to come on at 215 deg.F. Depending on the calibration of the thermosensor, it may be a little higher or lower.
If it gets over 220 and the fans don't come on, something's haywire and should be checked out.
They are very quiet, and don't flow a lot of air, so I have to take a good look at 'em to see if they're running. Got used to fan on my dad's KZ1300, sounded and felt like a freakin' Cessna when it came on.