Greetings Folks, I have an older (20+ yrs) Trane gas furnace. Became aware that it wasn't heating properly. Pulled the front cover and noticed that after the thermostat kicks on, the fan starts, the igniter glows, flame kicks on (all burners). Then, maybe 10 seconds after that, the flame goes out. I'm anticipating that I'll need to call a professional in. But I'm always grateful to get an experienced opinion here first on possible causes and solutions. Any suggestions/information will be greatly appreciated! Thanks!!

[left]Hello, looking for some help with my Carrier 9200 furnace. Noticed that it wasn’t running the other evening, so I went and found the error code 31 (pressure switch or inducer). [left]No blockage in the exhaust or intake pipes. The small tubes connecting the pressure switch to the burner and condensate pump are also clear. What I noticed while I was checking these tubes is that the inducer fan is hitting its housing when it turns. When I was initially looking at the furnace I turned on the power, blower came on for about 90 seconds and then just a humming sound - nothing else. After a few tries, the inducer fan began to start up, however it was so loud that I shut it down right away. Took the inducer assembly apart and found no issue inside. When the assembly is out of the furnace, the fan turns with no noise. When I put the assembly back in the furnace, the noise comes back. It seems like the fan never gets up to speed due to the fan hitting it’s housing. After some research, I’m wondering if the motor grommets could be the culprit - the furnace is about 20 years old, and they do appear worn. Questions: 1) Could the grommets be causing the inducer fan to behave this way? When I pull back on the motor it does seem to resolve the noise. 2) if the fan does not get up to speed - would this cause the furnace not to start up properly? Trying to figure out if this is my only problem. See attached photo of the grommets on the inducer fan assembly.[/left][/left]