SerialAtlas
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Water heaters date-code guide

A. O. Smith serial number lookup

A. O. Smith is a major North American water-heater manufacturer. A common serial style begins with year and production week.

Parent
A. O. Smith Corporation
Common code
A widely used style begins with two digits for year and two digits for production week (YYWW).
Reviewed
August 8, 2026

Instant equipment lookup

Decode the manufacturing date

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Equipment type

Using A widely used style begins with two digits for year and two digits for production week (YYWW).

Type exactly what is printed. Spaces and dashes are ignored.

Optional: add model number for capacity cluesAdd model

Model decoding is labeled as a clue unless the exact format is documented.

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EQUIPMENT DATA
MODEL24ABC636A003
SERIAL5019X30312
WeekYear

See exactly how the code was read

SerialAtlas highlights the date characters, names the matching rule, and shows alternative interpretations when the code is ambiguous.

  • Current age calculated automatically
  • Confidence and rule source shown
  • Optional model-capacity clue

Evidence-led route update

A. O. Smith date-code evidence

If you need to estimate an A. O. Smith water heater’s manufacture age, read the serial from the rating plate rather than the model number.

Record the A. O. Smith year-week prefix with the model

A widely used style begins with two digits for year and two digits for production week (YYWW). The verified A. O. Smith water-heater family begins with year and production week (YYWW). State and American Water Heater pages use that same parent-family evidence with their own label context. The verified A. O. Smith water-heater family uses year and production week at the front of the serial. Capacity, fuel or power, and the complete label keep the YYWW evidence tied to the correct tank or heat-pump family.

Worked example: 0950A12345

0950A12345 — The verified decoder reads this fixture as Week 50 of 2009. The date is a manufacture estimate, not an installation date.

When an A. O. Smith product is commercial or specialty

The common residential fixture is not a universal commercial decoder. If the equipment or label falls outside the documented family, stop at the cautious reference result and use official A. O. Smith support.

Model number vs. serial number

The A. O. Smith model identifies the product family and the serial supplies the age estimate; official support needs both identifiers. Record capacity, fuel or power, model, and serial so official support can distinguish the product family when a warranty question is involved.

Limits and official support

Commercial and specialty A. O. Smith products require confirmation from the full rating plate. If the result affects warranty, registration, parts, safety, or replacement decisions, use the complete model and serial with the manufacturer or a qualified professional. SerialAtlas is an independent reference, not an official warranty lookup or warranty coverage decision.

Open A. O. Smith support route

How to read a A. O. Smith serial number

A widely used style begins with two digits for year and two digits for production week (YYWW). SerialAtlas removes spacing and punctuation, then applies only the documented rule families mapped to A. O. Smith. The lookup remains in the browser.

Try this documented-style example0950A12345Load example

Equipment covered

  • gas tank water heaters
  • electric tank water heaters
  • heat-pump water heaters
  • selected commercial units

Commercial, imported, very old, specialty, and private-label equipment can use a different code. Confirm the full rating plate before accepting a result.

Where to find the rating plate

  • Upper or lower side of the tank jacket
  • Near the gas control valve on gas models
  • Behind an electrical access panel
  • Side or bottom edge of a tankless cabinet

Why more than one date can appear

Two-digit years and repeating letter cycles can point to more than one era. SerialAtlas ranks the plausible dates but keeps materially different alternatives visible. Label design, refrigerant, installation records, and product literature can resolve the era.

Source and verification

Inspector Handbook open reference data (CC BY 4.0). Independently implemented and reviewed August 8, 2026.

Open reference source

What this result does not prove

A manufacture date is not an installation date, warranty decision, recall match, condition assessment, or replacement recommendation. Confirm high-stakes decisions with the manufacturer or a qualified professional.