My Hydroflame 7916 furnace started squealing the other night, got louder and louder, but kept putting out hot air. I turned it off since I couldn't sleep with all that racket, and I didn't want to risk any (more) damage to it.
I pulled it out this morning, which turned out to be pretty simple. I pulled out the blower unit (motor with fan on both ends) and looked for wear points on the fans and housing that I would expect to see if either fan was contacting the housing. Nothing evident. I tried running the fan motor as fast as my drill would make it go (1000 RPM?) and no squealing noise. I've wondered if the fans could have slipped on the blower shaft but the little hex screws on those puppies were locked down so tight that I could get only one of them off. That fan fit so tightly on the blower shaft that I had to gently use a gear puller to get it off. I have enough hammers that I should be able to get it back on.
So should I replace the blower motor on a bet (more than $125), replace the whole unit ($514), or does someone have some suggestions of what else I can try/check? I've gotta have this thing in good shape in a few weeks for our Fall trip.