I know next to nothing, so I watched a youtube video explaining the steps of how a gas furnace works.
https://www.youtube.com/watch?v=tVLtJwix-_8&t=185sMine seems to be spending an extended period of time where the inducer fan is running before the pressure switch closes. It used to spend like like 10-15 seconds in that step, but starting earlier today, now might run for a minute or so, before the igniter lights things up. According to the video, that inducer fan will run until the pressure switch activates, which happens when there's enough airflow in the heat exchanger.
If the system is spending a long time running the inducer fan before the switch closes, is that likely to be just a bad pressure switch, or something else affecting the actual pressure/airflow in there?
