How do I tell the age of an Armstrong Air furnace or air conditioner from the serial number?
Thursday, June 14, 2018
The 8th digit of the serial number, which will be a letter (and typically the next to last digit) denotes the year of manufacture for units manufactured from the 1980s to the early 1990s:
A = 1980 I = (not used)
B = 1981 J = 1988
C = 1982 K = 1989
D = 1983 L = 1990
E = 1984 M = 1991
F = 1985 N = 1992
G = 1986
H = 1987
An example, shown below, is: A 10322EDB
The next to last letter indicates it was manufactured in 1983. Here’s an example of the nameplate from that era.
Beginning in the early 1990s the third and fourth numbers are the year of manufacture, followed by a single letter and more numbers, so the the condenser unit with the serial number below was manufactured in 2007.
There was also a format used for a while that placed the year of manufacture at the 7th and 8th digits of the 10-digit sequence that is all numbers. So, for example, serial number 5258470429 would indicate a 2004 year of manufacture.
To determine other key specs of your HVAC system, see one of these other blog posts:
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To learn more about heating and air conditioning systems, see these other blog posts:
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