AO Smith age?

Specific Inspection Topics Plumbing Inspections
1

Does anybody know how to ID the age on AO Smith heaters? The serial number has several combinations that could be believable dates.

2

Here:

3

Thanks Larry,
I had one that was GB89009298… I wasn’t sure if it was 89, 92 or 98, or 2000 for that matter.

4

1989