Lennox Furnace age please

Serial # 5369K

I think its 1969 based on the second set of digits (69) but just want to make sure.

Prior to 1974, the first two digits will be year, and the third digit is the month

1953, according to this.

It is an older dating system I have in my library and may be wrong…

Charles, if you have the model number I can see if prestons lists it



Hi Gerry,

The only other number I found on the serial # placard was the identification number. Not sure if this is the same as the model number or not. GS8D 105 DM

Thanks for the help


That model was made from 1967 to 1969.

Thanks Larry