Seasonal malfunction
I know about 8 different people whose furnaces all failed in the last week or two. And on Wednesday night, I became one of them. Ordinarily I have no stomach for home repair, but nothing motivates my ingenuity quite like being freezing cold.
So after spending a frigid evening surfing furnace repair technician forums, I now know all about pilot provisioning trouble codes, limit switches, and filtration air flow faults. And I only had to bypass 1 of my furnace's 6 safety sensors in order to get it working again.
Sleep tight!