Furnace age

[Randy D. Stufflebeem]

York

Mod: TG9S080B12MP11A Ser: WOB9591574

Thanks in advance

Randy

[Bill Smith]

For the old system I get either 1972 or 1993 for the year. Are you sure that the "O" isn't a "C" - the second letter is usually the month (except for "I") and December is "N".
The newer system uses a second/fourth digit system for the year. If that is the case - it's an '09 unit.

[Russel Ray]

York has either two, three, or four letters at the beginning. For those with three or four letters, the third letter is the year, in this case 1972 or 1993, as Bill said.