Permaglas (A.O.Smith) Furnace age?

I came across a Permaglas (A.O.Smith) furnace and cannot find the age off the serial #. It is a:
M# LU100-1 L 502 AMA
S# 204 59 7C1476
I’m thinking 1976 but cannot confirm anywhere on the web. Any help is much appreciated.

From what I have and assuming it is a water heater and not a furnace (as stated) it is probably 1959. I could help you more with more information.

  1. Age of home?
  2. Type of unit (electric, gas, etc.)?
  3. Picture of data plate.

Thanks Les! It is a forced air furnace. I was a journeyman Sheet Metal Worker by trade and I am not familiar with this brand as a furnace either. The home was built in 1958 so the '59 makes sense in that fashion. I do not think it is that old having seen furnaces from several different decades. I have pictures but I will have to do some investigating to upload. Thanks for your help. - Kevin.

In that case I would go here: and contact them.

I still say 1959.