Factory + year/week
G051650885
Week 16, 2005 (around April).
Furnaces & AC / Tempstar

Look for “Serial” or “S/N” near the service connectionsDark = year, orange = month or week.
Week 16, 2005 (around April).
Supports the factory-letter + nine-digits ICP layout. The annotated reference identifies a production week; some page text incorrectly calls it a month. Earlier recall and short serials are excluded.
References checked 2026-10-26.
Independent reference tool, unaffiliated with Tempstar. Sources & method