The SAP structure begins with a letter, a digit, a month letter, and another digit. Positions 2 and 4 combine to form the two digit year, while position 3 gives the month. For example, split serial number W1L6362897 as W | 1 | L | 6 | 362897. The year digits 1 and 6 form 2016, and L means October. Therefore, this serial number gives October 2016. Appliage checks both structures and returns one manufacture month when the year is unique or every date allowed by a repeating year letter. The model number does not change the York age result.
Appliage decodes two York date structures, and both give a month and year. In the SAP structure, position 1 is the factory, position 3 is the month letter, and positions 2 and 4 combine into the two digit year. In the four letter structure, position 2 is the month letter and position 3 is a year letter that repeats every 21 years. York Age Rules below has both tables.
Go by the opening characters, not by an assumed changeover year. Four letters at the start use the repeating letter table and can give dates 21 years apart. A letter, digit, letter, digit opening uses the SAP structure and gives one year.
York Age Rules
| York structure | Factory field | Year field | Month field | Other fields |
|---|---|---|---|---|
| Legacy letter structure | Position 1 | Position 3: repeating year letter | Position 2: month letter | Position 4 is product type; remaining characters are the unit sequence |
| Later SAP structure | Position 1 | Positions 2 and 4: combine the two digits | Position 3: month letter | Remaining characters are the unit sequence |
- legacy 1 factory letter
- legacy 2 month letter
- legacy 3 21-year cycle letter
- legacy 4 product type
- SAP 1 factory letter
- SAP 2 + 4 two digit year
- SAP 3 month letter
- remainder unit sequence
The factory letter identifies where the equipment was made. In the legacy structure, position 4 identifies the product type. The remaining characters identify the individual unit. These fields help York identify the equipment, but they do not influence its manufacture date.
York Month Codes
| Month code | Manufacture month |
|---|---|
| A | January |
| B | February |
| C | March |
| D | April |
| E | May |
| F | June |
| G | July |
| H | August |
| K | September |
| L | October |
| M | November |
| N | December |
Both York structures use this month table. The table skips I and J, so K means September and L means October.
Legacy York Year Letters in Position 3
| Year letter | First cycle | Second cycle | Third cycle |
|---|---|---|---|
| A | 1971 | 1992 | 2013 |
| B | 1972 | 1993 | 2014 |
| C | 1973 | 1994 | 2015 |
| D | 1974 | 1995 | 2016 |
| E | 1975 | 1996 | 2017 |
| F | 1976 | 1997 | 2018 |
| G | 1977 | 1998 | 2019 |
| H | 1978 | 1999 | 2020 |
| J | 1979 | 2000 | 2021 |
| K | 1980 | 2001 | 2022 |
| L | 1981 | 2002 | 2023 |
| M | 1982 | 2003 | 2024 |
| N | 1983 | 2004 | 2025 |
| P | 1984 | 2005 | 2026 |
| R | 1985 | 2006 | 2027 |
| S | 1986 | 2007 | 2028 |
| T | 1987 | 2008 | 2029 |
| V | 1988 | 2009 | 2030 |
| W | 1989 | 2010 | 2031 |
| X | 1990 | 2011 | 2032 |
| Y | 1991 | 2012 | 2033 |
The four letter year sequence repeats every 21 years. Johnson Controls publishes all three columns shown above. Appliage leaves out any candidate that is later than today.
Later York SAP Year Digits
| Positions 2 and 4 | Manufacture year | Example opening |
|---|---|---|
| 0 and 7 | 2007 | W0G7 |
| 0 and 9 | 2009 | W0H9 |
| 1 and 6 | 2016 | W1L6 |
| 2 and 6 | 2026 | W2A6 |
Take the second character as the tens digit and the fourth character as the ones digit. For example, W1L6362897 contains 1 and 6, which form 16 and therefore mean 2016.
On a worn plate, the letter O sometimes gets copied into a year digit position. The letter O is never valid there in either published layout, so Appliage treats it as the digit zero and says so in the result. Field serial WOK6912254 is an SAP serial with O typed for zero: 0 and 6 form 2006 and K means September, so it dates to September 2006.
The SAP layout only goes back to October 2004, when York adopted it. A serial in the SAP shape whose year digits land before 2004 comes back with no date instead of a guess.
York Serial Numbers Appliage Cannot Find the Age
A legacy serial number must begin with four letters and use a valid month and year letter from the tables above. A later SAP serial number must begin with a letter, digit, valid month letter, and digit. If the serial number matches neither structure, Appliage returns no manufacture date.
York serial numbers from before 1971 use other structures and cannot be decoded with these rules. Entering the model number does not change the date result or choose among the repeating year cycles because Appliage does not have a catalog of York model production periods.
The manufacture month can differ from the installation date and warranty start date. A dated installation, purchase, service, recall, or factory record may resolve a repeating legacy year code.
York Commercial Equipment Is Not Dated Here
Appliage covers residential York equipment. York’s commercial families, the Sunline D series and Predator Z series packaged rooftop units and the YK, YT, YD, YVAA, YVWA, YMC2, YCIV, YCAL, YCWL, YLAA, and YLUA chillers, are outside that scope: when the model number identifies one of them, Appliage declines instead of guessing a date.
Commercial and residential units shared the same legacy letter layout before 2005, so a legacy result from the serial alone carries a commercial caution with it. Check the model number on the cabinet before relying on a legacy date.
Coleman, Luxaire, Champion, and Fraser-Johnston
Coleman HVAC, Luxaire, Champion, and Fraser-Johnston equipment use this York and Johnson Controls serial system. Select the name printed on the cabinet and copy the serial number from that same rating plate.
Coleman camping gear is unrelated to this HVAC system. These date positions apply only to heating and cooling equipment.
Sources
- Johnson Controls serial number reference (SI0418). The reference explains both serial formats and their year and month letters. Archived copy.
- UPG furnace service letter (ST-028-07). The service letter includes a York residential furnace serial with a known date. Archived copy.
- UPG furnace service letter (ST-045-09). A second residential furnace serial appears in this service letter.
- York warranty and registration
- Coleman warranty and registration
- CPSC: York Diamond 80 furnace recall (00-003). The affected serial prefixes run from EECM to EGEM.
- CPSC: York, Luxaire and Coleman furnace recall (01-523). The notice lists furnace prefixes WFKM and WGKM.
For other brands, see our appliance serial number lookup.
