I just bought a house and I need help figuring out my attic fan and all the gadgets connected to it.

http://www.freeimagehosting.net/uploads/39264f00b5.jpg

One appears to be just an on/off switch, then there are two boxes with temperature dials, and I have no idea what the other one does. It seems like a lot of stuff just for an attic fan. The previous owner cannot help. Maybe someone who knows fans can help me with some info. Any details you can provide are most appreciated. Thanks!

The reason I'm asking is because the fan goes on a times when it's not hot. There doesn't seem to be any logic to when it runs, but there's so many gadgets on there that I'm hoping they serve some purpose.
I can see one thermostat, but why two? And what's the other thing connected? If it was just a switch and a thermostat, then it would be no problem. It's the extra stuff that is the mystery.