Need Armstrong furnace age

Model number: G7A100DC12-11
Serial: A25175KKA

House was built in late 50s. The only number I see in the SN is 75, but it didn’t look that old.

Thanks for the help!:mrgreen:

I believe the second K is 1989…and the manufacture age is, typically, within 2 to 3 years of the ANSI date.
Use the search function above for further info…


According to my reference the first K is the month (oct) and the 5 before the K would be 05-95-85-75 take your pick


Thanks, Marcel.

What reference are you using Charley?

I was looking at this one and it was not real clear on Armstrong

I have what appears to be an older model Armstrong and there is no sense of sending a photo because it is so deteriorated that I have to move the name plate around in the sun just to read it… Mod # SA36SA-1 (assuming 3 ton)
Ser # 22667EMA (assuming 1967?)

In that style of serial number the E=May and the M=1991