If we had an oldest boiler contest, I would enter this one!
HB Smith Oil Fired Boiler
with a Herod Oil Burner
Home was built about 1890
Not original (most likely wood or coal) and not sure of the age of the Boiler.
Still plenty of 120 year olds in this town though the numbers dwindled during the last boom period thanks to rental - condo conversion.
Vintage 1937 boiler, originally coal fired but converted to oil.
Not much goes wrong with them internally.
They were built like Sherman Tanks…
I have a boiler for my hydronic system, and we expect about 35 years out of it, unless it leaks or somesuch…