Going to start with mine. The Lennox Strategos line from the early 2010s. Anything pre-2015. The amount of times I’ve been up there fighting the same control board failures, the same blower assembly issues, the same condensate problems…
Owners refuse to replace because “”it still works.”” It barely works. I make a decent living off it though so I shouldn’t complain.
What’s yours? Brand, model, why.