I have a trane xl80 furnace. It was working fine till a week back when I woke up one morning smelling some kind of strange smell (not exactly a burnt smell but similar). I found the furnace working and the blower was off. I realized that to be problem and hence turned the heater off. The fan would not turn on even if it manually was set to ON. I then started the AC and even then the blower wouldn't come on. I just turned it off and then spent some time checking the breakers for any trips. After some time the blower started working when set to ON and also with the heater. The same problem happened again another day. This time I was looking for the blower turning off and immediately noticed that the furnace was still on. I think the problem was something to do with fan control unit, but not sure what. I think some control is getting over heated and turning the fan off. I have the complete heater and fan unit turned off till this is resolved.. wanted to check it there is any thing I can do to check/fix things before calling the service folks.

Thanks in advance.

S

From everything you have said I'm geared to think it is a bad blower motor or run capacitor

Had a service person look at it today. As luck would have it the blower worked fine when he was there. The service person said if there is a problem it could only be with the control unit (white rodgers ) and that I may need to replace that. He gave me a 800+ quote to replace it. Later on in the night when the fan didn't start along with the heater I checked the control lights. I seemed to be either 2 flashes or 3 flashes (didnt see it long enough, restarted the heater and blower started working). The control schematic said 2 flashes is no gas indicator, which seemed unlikely because I could see the burners working fine. 3 flashes seems to indicate pressure switch problem. Couldn't figure out what that could be. Any ideas?
Since I wasn't totally convinced by the this service persons answers, planning to get the original installer to take a look again.

Don't pay any 800 dollars until you know what is wrong.