Bard oil furnace age?

[Tom Raymond]

Besides having the dumbest cover system ever, the numbers don't look anything like what's in the decoder chart.

model F85H12

serial L746180

There was a service record showing cleaning every year, and more than a few repairs, going back to November 97. No manuals. It looks older than that, but it's way newer than 1954 when the house was built.

Thanks in advance,

Tom