The fan does not use an exhaust hose as it is installed in the factory position. The "custom" thing about it is that it is a variable speed A/C fan that allows one to dial it down for printing and crank it up in between. It works so darn well that I would consider upgrading any enlarger head fan to this, all for a whopping $25...
I think what probably happened was that my struts were not the way they should have been and I got away with it sans 45S head but not with it on. That's the only thing I can come up with as when I broke it down yesterday, I inspected it carefully and found nothing out of the ordinary.
It's in storage now until I get a proper darkroom space. As far as my needs are concerned, they have been met fully by employing the use of a new enlarger, so I really don't know what else to say.