I have posted before regarding this fan but today was the last straw for me, this thing is HOT. REALLY HOT! I noticed a vibration in the floor and traced it to this fan. It has always been warm so I have been watching it. But today it was out of limits for me so I disconnected it. Questions: does this thing usually get this hot? Has the thermostat failed? Is the whole thing toast because it got so hot? Do I even need it?
My guess is that the bearings are shot. Soon enough it will freeze up. I would replace it or try and r&r the bearings. It may not be mission critical, but will keep the electronics cool enough to prevent early failure.