How old is my Slant/Fin boiler?

Serial number age decoder for Slant/Fin boilers: 1 format era, the decode rule in plain English, transcribed tables, and the official lookup.

Format eras

era not stated VERIFIED
A#######

How to read the serial

era not stated formatVERIFIED

Shape A####### · example G0017649 / L43040967 / 444527 / Q70069 · confidence high

Documented but not evaluated by the decoder: no year decode text.

Trap: NO date encoded (building-center, confirmed absence). Decode method = ANSI/CGA revision year on plate (unit is no older than that year, typically within 4-8 years).

Where the data plate is on a boiler

On the jacket: a plate or sticker on the front or side of the boiler casing, sometimes behind a removable front panel next to the gas valve or control.

General guidance, not brand-specific: the owner's manual or the installer can point to the exact spot. See the data plate guide.

For scale only: the InterNACHI Standard Estimated Life Expectancy Chart for Homes lists Boiler at 40 years of expected service (nachi.org). That chart is a guideline, not a prediction for your unit.

Official lookup

No online serial lookup was found for Slant/Fin in our research. The manufacturer's customer service line, the installer's invoice, or a printed date on the plate are the remaining authorities.

What we could not confirm

The era not stated format is documented but not decodable here: no year decode text.
No official online lookup URL was verified for Slant/Fin.
Sequential serials of varying shape (G0017649, L43040967, 444527, Q70069); numbering system was never published and the company can no longer be contacted. Use ANSI/CGA compliance year on the rating plate or the gas-valve date stamp.

Sources

https://www.building-center.org/slant-fin-hvac-age/