Lennox serials start with a two-digit plant code that is often mistaken for the date. The year is the third and fourth digits and the letter after them is the month. Armstrong Air, AirEase, Ducane, Concord, Allied and Aire-Flo are Lennox companies and use the same rule on newer equipment.
The first two digits are the factory, not the date. The next two digits are the year and the letter after them is the month (A is January, M is December, I is skipped).
5898G07568 reads as July 1998.
Two sources agree PickHVAC, Hunker, Waypoint Property Inspection, Energy Trust of Oregon furnace chart, InterNACHI inspector forum
On ten-digit all-number serials the seventh and eighth digits are the year and the last two are the week.
4140720328 reads as week 28 of 2003.
Two sources agree Building Intelligence Center, McGarry and Madsen Home Inspection, Energy Trust of Oregon furnace chart, PickHVAC
A central AC condenser usually lasts 12 to 15 years. In hot climates where it runs most of the year, 10 is more typical; in the north, 20 is possible.
How long does a central air conditioner last? · Should I replace my air conditioner? · Bryant, Lennox, InterNACHI (7-15)
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Galvanized, polybutylene, cast iron and the sewer line: what fails, what it costs, what insurance won't cover and how to decide.
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