Update:
The Heat is ON!
I finally got around to entering the depths of Mordor which is the basement of my house, and saw that the set screw had come loose from the belt wheel connection to the fan, which in turn (no pun intended) came loose from the fan, and was lying there just waiting for someone (me) to come along and help.
Which I did.
Because I got cold again.
Now, if the temperature happened to be in the upper digits, say 10 degrees plus, that poor little wheel would be laying there till fall, cause I would just say "Ach, it's warm enough...I'll just wear wool. Sorry, Peter!"
Well, lucky Pete.
Cause it's hard to look cool in wool.