Another Furnace Age ?

These three furnaces were from a 1988 build 5800 sq ft home. Any idea on age?

M-THP120A960A1
S-CO8302646

M-THP050A936A
S-CO8301741

M-THP120A960A1
S-CO8302645

Around here the furnace is only used 6 weeks a year so if it is originial it would not be surprising.

The Furnaces were Trane.

Trane used alpha codes in their serial numbers to determine year of manufacture. They started this in 1987 with the letter B and skipped the letters I, O, Q, U, Z
In 2002 they started their serial numbers with the year it was built.
The first letter of the serial number gives the year of manufacture as follows:

9=2009 8=2008 7=2007 6=2006 5=2005 4=2004 3=2003 2=2002
**Z=2001 R=2000 P=1999 N=1998 M=97 L=96 K=95 J=94 **
H=93 G=92 F=91 E=90 D=89 C=88 B=87 S=86 Y=85 X=84 W=83
U=82(seventh digit) T=81(seventh digit) O, A=80(seventh digit)

Looks like 1988 on all three.

Jae,

Thanks a bunch for your help. I had a stinkin suspicion that were 88 but did not want to guess. Thanks for the Trane info. Will save it for later. Take care.