Only WeatherKing AHA-family heat-pump air handlers matching the manufacturer parts-list legend
The optionalT is a sequence-manufacturer marker, M is production location, followed by two-digit week and year. The century is not established automatically; a user-supplied decade can narrow it.
Confirm the WeatherKing AHA-family air handler and the documented optional T/M-plant serial legend before selecting this system.
Reading your result
WeatherKing lookup questions
Why does the year code match more than one year?
Some systems reuse letters or only encode the last one or two year digits. Every supported interpretation is retained. A decade supplied from reliable records can narrow the reading; the tool does not automatically pick the newest year.
Does the serial identify my exact model?
Usually the model is a separate plate field. Where published serial ranges actually identify a model, the result shows model candidates and links to their manuals. Overlapping ranges remain ambiguous.
Can I share the result?
After a lookup, the address includes the serial in a fragment beginning with #serial=. Use “Copy share link” to share the serial and selected context. Opening the link runs the same lookup. The fragment is not a query-string result page.