We've got a new Trane XL90 gas furnace. Wife turned it on yesterday
and it didn't fire up. When I got home from work, I took the lid off &
started poking around. Discovered that the combustion air fan (I think
the svc guy called it the "inducer") was bound. (Push in cover limit
switch, hear HMMMMMMMM at 60Hz, release limit switch, start feeling for
hot things, identify stuck motor...)
Since it's in warranty, I called service & griped. First thing he
asked was whether it was a 90% effeciency furnace. When I told him it
was (PVC exhaust), he immediately asked if there was a bird in the fan.
Yeah, that's the first thing I think of when a fan motor
fails--there's a dead bird in it!
Took the fan off, removed the dead bird, and everything works fine now.
Any good troubleshooter looks for horses, not zebras, and this guy
nailed it on the first try. So, is this a common thing? Repair dude
said you can't put a grill over the exhaust because it'll ice up &
clog. Is there nothing that can be done to prevent birds from getting
into my furnace?
The motor has a thermal overload (thought it was really hot), so
probably no damage when this happens again. Still, WTF??