Letter-cycle year codes

Several makers encode the year as a letter. Letters run out, so the cycle repeats, and a serial alone cannot say which pass through the alphabet it belongs to.

The decoder shows every candidate year inside the format's era instead of picking one. Use the ANSI date, a printed manufacture date, the plate's style, or the official lookup to choose. The tables below are transcribed from the sources cited on each brand page.

Armstrong Air, 1978 to 1992 VERIFIED

The Allied-Commercial page TEXT swaps the positions (year=7th, month=6th); the Armstrong Air chart image and the AirEase/Magic-Pak text agree on month=7th, year=8th, which is used here. Plate may show a space after the first letter (A 25175KKA).

Armstrong Air decoder and sources

Bard, 1980 to 1980 VERIFIED

Used only April-May 1980.

Bard decoder and sources

Bard, 1962 to 1980 VERIFIED

Chart typo '19783' for N corrected to 1973. 5 OR 6 leading digits. Example = Oct 1978.

Bard decoder and sources

Bradford White, 1984 to present VERIFIED

Year letter repeats every 20 years (A = 1984, 2004 AND 2024; as of 2026, A/B/C are triple-ambiguous). Disambiguate via ANSI compliance date on the plate, rating-plate style, or the official my-water-heater lookup which returns the exact manufacture date. Special case: 'OA' serials exist due to a computer error, all made January 1997.

Bradford White decoder and sources

Bryant, 1980 to 1984 VERIFIED

US units = letter then digit (W4D14008); CANADIAN units REVERSE the first two positions (4WD14008 = digit then letter). Style used only 1980-1984 by BDP (Bryant/Day & Night/Payne, a Carrier subsidiary).

Bryant decoder and sources

Bryant, 1980 to 1984 VERIFIED

Canadian-built BDP variant of the 1980-84 style; positions of month and year are swapped vs U.S. units.

Bryant decoder and sources

Carrier, 1960 to 1979 VERIFIED

Supersedes formats.json Carrier 1960-79 rule whose table was not transcribed: this is the full table from the Bryant page text. 46U152456 = week 46 of 1967; 2W13270 = week 2 of 1969. Overlaps the 1970-79 A167890 style (letter-first) - distinguish by leading digit(s).

Carrier decoder and sources

ClimateMaster, 1998 to present VERIFIED

H is out of sequence (1998). Chart stops at 2017; anything after is extrapolation. Example = 2007 week 11.

ClimateMaster decoder and sources

Crown, 2004 to present VERIFIED

Applies to the SERIES field, not the CROWNB... serial. Chart last revised Jan 2023; years after 2023 are extrapolation.

Crown decoder and sources

Daikin, 1995 to 1999 VERIFIED

Only 1995-1999; last 2 digits = engineering revision.

Daikin decoder and sources

Daikin, 1971 to 1994 VERIFIED

1971-1994 only; same shape as style 5 (digit at position 2 = 1995-99, letter = 1971-94).

Daikin decoder and sources

Daikin, 1974 to 1988 VERIFIED

Daikin-McQuay condensing units prior to 1988. 17-char serial with the only letter at position 11.

Daikin decoder and sources

Daikin, 1964 to 1970 VERIFIED

1964-1970 McQuay fan coils only.

Daikin decoder and sources

GE Appliances, 1977 to present VERIFIED

Official GE Appliances page. Year letter repeats every 12 years, so GA = April 2001 or April 2013 (GE's own example); GE says to use the print date on the owner's manual (e.g. 02-20) to pick the cycle, or contact them with model + serial. Building-center's Hotpoint page text says '1st = year, 2nd = month' - that is backwards (its GE page, GE's page and the VZ902110G plate stamped NOVEMBER 1988 all say month first). Pre-1977 codes (E=1969/1948, N=1972/1956, two-letter codes AY..DB for 1961-68, B/C/J/K for 1945-53) are in the official table but rarely matter. Worked examples: VZ902110G = Nov 1988 (building-center plate photo), ZV700153M = Dec 1975/1987/1999, LR821547C = Jun 2020, RL059433C = Aug 2018, ZR525322 = Dec 1996, LV227019H = Jun 1999 (Hotpoint), RD166115R = Aug 2002 (Hotpoint) (appliancedates).

GE Appliances decoder and sources

GE Zoneline (PTAC), 1944 to present VERIFIED

Year letter repeats every 12 years - narrow with ANSI date, condition, model era. Post-2013 assignments are extrapolated, not sourced. Same system as GE/Hotpoint/Cafe/Monogram appliances (batch 12).

General Electric (legacy central HVAC, pre-1982), 1965 to 1985 VERIFIED

Style 3 puts the same two letters at the END (409295HM). Example = Aug 1976.

General Electric (legacy central HVAC, pre-1982) decoder and sources

Goodman, 1990 to 2013 VERIFIED

Goodman-brand PTACs built by Daikin only; ends with P or D; style ended shortly after the 2012 Daikin acquisition. This transcribes the table formats.json flagged as 'table-not-transcribed'. Example 5FU5472618P = June 2008.

Goodman decoder and sources

HTP, 1994 to 2011 VERIFIED

Ignore a parenthesised prefix like (21). Official examples: C18D12345 = Mar 18 1997; H04K12345 = Aug 4 2004; L09P12345 = Dec 9 2009. Month table INCLUDES I (unlike AO Smith).

HTP decoder and sources

ICP, 1980 to 1993 VERIFIED

Digits 0-3 are double-valued (1980s or 1990s). 8-digit all-numeric; sample 30512345 is a building-center sample, not a photographed serial.

Lochinvar, 1979 to 2011 VERIFIED

Chart only lists 1993-2012 although the style ran 1979-2011; letters repeat every 20 years (K = 1973/1993/2013) exactly like Bradford White. Official example KJ-1000130 = Sept 1993. Gas/electric/solar, commercial tank, Hi-Power, oil-fired series.

Lochinvar decoder and sources

Lochinvar, 1968 to 1981 VERIFIED

Copper-Fin water heaters (CFW) and boilers (CFB) 1968-1981. 5Y013 = May 1978. Letters before P (1968-69) not in chart.

Lochinvar decoder and sources

Maytag, 1966 to 2010 VERIFIED

Pre-Whirlpool Maytag Corporation format (Maytag, Admiral, Magic Chef, Jenn-Air, Amana 2002-2006, Norge, Hardwick, Crosley, Caloric, Modern Maid). Year letters repeat every 24 years (E = 1980 or 2004); the letters are NOT alphabetical by year. Whirlpool phased it out after the 2006 purchase but appliancedates shows a Jenn-Air range 16240783NR built Sept 2008 in this code, so the era overlaps the Whirlpool style through ~2010. Worked examples: 12772864EL = Jun 2004 (Amana dryer NDE2330AYW), 17657865KM = Jun 1994 (Jenn-Air S156), 12150883QY = Nov 1996, 16240783NR = Sep 2008, 717486QX = Dec 1972 (6-digit sequence), 19346732EG = Apr 1980/2004 (building-center). Alliance Laundry still uses this exact letter cycle on its European-built machines (see Speed Queen rule).

Maytag decoder and sources

Samsung, 2001 to present VERIFIED

Letters repeat after 20 years (R = 2001 AND 2021, T = 2002 AND 2022). The 2006 row reads 'A-L' on the chart (unclear whether any of A-L meant 2006); B/C/D/E/G/H/J/K/L are also assigned to 2011-2018, so treat 2006 as an exception. Serial length varies (15 chars typical); position count must be from the left. Example J0V07DDC400695M = C,4 = Apr 2012.

Samsung decoder and sources

Samsung, 1997 to 2004 PARTIAL

Chart only covers 1997-2004 (R22 era); the letters are the same series as the appliance chart, so later HVAC serials probably continue it (Y=2005, Z=2010 ...) but that is unverified. Example P1AN800011 = N,8 = Aug 2000.

Samsung decoder and sources

Speed Queen (Alliance European-built), 2009 to present VERIFIED

Alliance product-information insert D2288EN (April 2017) for its European freestanding/commercial washer-extractors (Primus/IPSO/Speed Queen EU lines): 'the last two characters indicate first the year and then the month'; example 520I000001DK = May 2015. Same letter tables as the old Maytag code. US-built Ripon machines use the YYMM numeric rule instead.

Trane, 1983 to 2001 VERIFIED

Letters are NOT in alphabetical order (S=1986, Z=2001, W/X/Y precede B). Style-3 (A92M07217, factory letter + YY + month) shares the leading-letter shape.

Trane decoder and sources

Utica, 1979 to 2001 VERIFIED

Year letters are NOT alphabetical (I-M = 1979-83, then A-H = 1984-91, then N-Y). HT11826 = Aug 1996.

Utica decoder and sources

WaterFurnace, 1985 to 2012 VERIFIED

A-F are double-assigned (1985-1990 and 2010-2015) - disambiguate by plate style/ANSI date. Chart lists D-F as 2013-2015 even though style 1 supposedly started 2012. Example = Sep 2004.

WaterFurnace decoder and sources

Whirlpool, 1990 to present VERIFIED

Year code REUSES letters: 2020-2032 repeat the 1990-2002 letters (X..L), and 2011-2019 are digits, so a 1990s letter and a 2020s letter are indistinguishable without model era. 1970-1989 used a single digit (0-9 twice). Note: the building-center chart shows W=2019 which is almost certainly a typo for W=2009 (9=2019 on the same chart) - flag for verification against a second source. Maytag pre-2006 and Amana pre-2002 used their own formats (ESTIMATE, not fetched).

Whirlpool decoder and sources

Whirlpool, 1990 to present VERIFIED

TABLE CONFLICT for 1999-2010: building-center (the table already in formats.json) says I=1999 J=2000 K=2001 L=2002 M=2003 P=2004 R=2005 S=2006 T=2007 U=2008 W=2009 Y=2010; appliancedates says J=1999 K=2000 L=2001 M=2002 P=2003 R=2004 S=2005 T=2006 U=2007 W=2008 Y=2009 0=2010; Sears PartsDirect (official Sears, current) says J=1999 K=2000 L=2001 M=2002 N=2003 P=2004 R=2005 T=2006 U=2007 W=2008 Y=2009 0=2010. Two of three sources put K=2000, Y=2009 and 0=2010 (the building-center chart has no 0 and uses I, which Whirlpool otherwise skips) so treat the building-center table as off-by-one for 1999-2010 until a Whirlpool document settles it. All three agree X=1990..H=1998 and 1-9=2011-2019, X=2020, A=2021.. Letters repeat every 30 years, so model era is needed to pick 1991 vs 2021. Worked examples: MX06404786 = 2020 wk 6 (appliancedates, Maytag dryer MED7230HW0); MB1402320 = 1992 wk 14 (appliancedates Kenmore); RA01xxxx = wk 1 of 1991 or 2021, FM644xxxx = wk 44 of 1986 or 2016 (Sears).

Whirlpool decoder and sources

Williams, 1984 to 2004 VERIFIED

Date-code sticker, separate from the data plate. Letters after 2004 not charted (a new cycle presumably started). Example = 13 Jan 1987.

Williams decoder and sources

York, 1971 to 2004 VERIFIED

Letters A-N repeat (1971-1984 vs 1992-2004): 21-year cycle. Some serials carry a parenthesized leading letter e.g. (S)EBHM062202 - ignore it. Style ran to Oct 2004, so 2004 has BOTH styles.

York decoder and sources