Age please

Forced air
Model # GSU165MF
SERIAL# 11320393

Luxaire – See York. Founded in 1939. On August 2, 1965, the original name of the company, C.A. Olson Mfg. was changed to Luxaire, Inc. with brand names Luxaire & Moncrief. .Luxaire was purchased by Westinghouse in 1955 then purchased by York in 1980. When there are three or four letters at the start of the serial number, the third letter is the year. A is 1992, B is 1993, C is 1994, D is 1995, E is 1996 and F is 1997, G is 1998, H is 1999, J is 2000, K is 2001, L is 2002, M is 2003, N is 2004, P is 2005, etc.

York is letters also.

That’s all I got.

Guess would normally be 2003 for that number. Does it look about 7 years old?

I would say by the rust, Older than 7yrs. Hard to tell. House is 100 yrs old.
Unit looks fairly decent except for the rust.

I hope you checked that flue and chimney.
Looks like a mid-efficiency from here.

I see issues in your flue,which look like moisture issues.
Is there a brick chimney with no liner?

No rain caps, water just goes right in.

Rain is not a concern.
More like unlined chimney taking acidic flue gas and condensing to eat at the brick and mortar.

How does the exterior brick look?

I have been looking at the debris under that hood along with the rust.

I think for a 100 yr old chimney, not too bad. did note some deteriated morter though. A few loose bricks at the top.

Looks bad enough.
The flashing does not look right, in the picture.

What is that support bar there?
The chimney does not look like it needs it.