Starting in the year 2000, same idea only it was a six digit date code following the serial number that is year and month. Example - JO-, this unit was built in October of 1984.

Starting in 1984, there was a four digit date code following the serial number that was month and year.

Call 90 if you get stuck.ColemanSerial numbers prior to April 1992=1st two numbers are month, then year, then series.After April 1992, 1st two numbers are year, then month, then series. 14th & 15th digits = Factory Code (01=OH 02=GA)Carrier, Bryant, Payne, Day & NightRecently (last 20 years or so) the first four numbers in the serial number represent the week and year.Previously, it was a complex series of letters and single digits.

1980 = A 6th thru 11th digits represent the Unit Identity Number.This serial number style was only used during the months of April & May 1980.June 1980 to Current Sample number 123 H 02 1st three digits = Compressor Part # 4th digit = Month5th & 6th digits = Year 80 = 1980 81 = 1981 82 = 1982 The year 2000 started the numerical numbering from 00.00 = 2000 01 = 2001 02 = 2002 Right on through to current date. 5th digit is the year of Manufacture.In this sample A represents 1980.

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