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.