Nice job! I had a fun one 2 winters ago, the glue on the pressure sensor switch just failed, I’ve never heard of this happening before. (Admittedly I’m not reading stuff about gas furnaces daily, but still…) The black piece and the white piece separated in the pic.

So the gas turns on, and the fan starts speeding up and there’s a pressure switch I guess to make sure there’s gas flowing, and the fan is blowing before igniting and starting the whole reaction, and since the switch wasn’t working, it wouldn’t ignite.

I tried to re glue the 2 plastic halves back together but the glue wasn’t holding, so I just zip tied the hell out of the thing, and its been working great for 2 years so far…