It took some digging, but I managed to find the specifications for the temperature limit switch in my High Efficiency heating system... for $7.62 I was able to buy a replacement from Grainger, and get it installed.
I strongly suspect if I had called for service, I'd be told I needed a new furnace, even though this one is less than a decade old.
I strongly suspect if I had called for service, I'd be told I needed a new furnace, even though this one is less than a decade old.