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Dating Furnace & Water Heaters

The following are brands furnaces and air conditioners are commonly found in southeast Michigan.  This list is not all encompassing, and mistakes are bound to happen.  A contentious effort was made to provide the correct information to assist in determining the age of the heating and cooling equipment, but due to the numerous manufactures and the variations of the dating codes, no liability can be assumed.

Amana (A member of the Goodman family of furnaces)

For units manufactured since the early 1990’s, the first two placeholders in the serial number indicate the year, and the next two numbers indicate the week of manufacture (YYMM).

American Standard (Trane)

Often, American Standard prints the month and year of manufacture on the date sticker.  If the date is not readable or present, American Standard uses several dating codes in their serial numbers.  The first code format would is the production year is the first numeral in the serial number followed by the week (YWW).  A second code format is the first placeholder in the serial number is a letter representing the month followed by two digits for the year (MYY).  An older code format is the first two digits of the serial number represent the year, and the next two digits represent the month (YYMM)

Armstrong

Armstrong uses three methods of imbedding the date codes in the serial numbers.  With the first method, the first two numerals of the serial number represent the year, and the next two numerals represent the week.  (YYWW)

The second method uses the first two digits of the serial number represent the week, and the third and forth numbers represent the year of manufacture.  (WWYY)

The third method uses the third and fourth placeholders of the serial number are numerals that represent the year of manufacture.  The letter after the year is a letter that represents the month.  (**YYM)

Bryant (Carrier, Payne)

For Bryant and Carrier residential HVAC products manufactured form 1985 to the present, the date code is embedded in the first four placeholders of the serial number.  Either the first four digits in the serial number is the week and year (WWYY), or the first two four digits are the year and month (YYMM).

For furnaces and air conditioners manufactured from 1980 to 1984, an 8-digit serial number was used with the first letter signifying the month (M=January…Z=December) and the numeral in the second position (1 through 4) represents the year.

For Bryant furnaces manufactured between 1964 through 1979, The first two numbers of the serial number are followed by a date code: R=1964, S=1965, T=1966, U=1967, V=1968, W=1969, X=1970, Y=1971, A=1972, B=1973, C=1974, D=1975, E=1976, F=1977, G=1978, H=1979.

Carrier (See “Bryant”)

Coleman (See “York”)

Comfortmaker

The first place holder in the serial number is a letter for the month followed by two numerals representing the year followed by two more numerals which represent the week (MYYWW).

Another method of dating some Comfortmaker equipment is the serial number starts with an “L” followed by two numerals the represent the year (LYY).

Ducane

Ducane uses several serial number date codes.  For example, the third and forth placeholders in the serial number is the production year followed by a letter for the month (**YYM).  Another variation of their code is the second and third placeholders are the year and the fourth and fifth placeholders are the weak (*YYWW).

Evcon (See “York”)

Fraser-Johnson (See “York”)

Goodman (Goodman brands include Amana, Janitrol)

For units manufactured since the early 1990’s, the first two placeholders in the serial number indicate the year, and the next two numbers indicate the week of manufacture (YYMM).

Heil (see International Comfort Products)

International Comfort Products (This product family includes ArcoAire, Kenmore, Comfortmaker, Heil, Tempstar) The first place holder in the serial number is a letter for the month followed by two numerals representing the year followed by two more numerals which represent the week (MYYWW).

Another method of dating some Comfortmaker equipment is the serial number starts with an “L” followed by two numerals the represent the year (LYY).

Janitrol (A member of the Goodman family of furnaces.)

For units manufactured since the early 1990’s, the first two placeholders in the serial number indicate the year, and the next two numbers indicate the week of manufacture (YYMM).

Lennox

After 1974, the numerals in the third and forth placeholder of the serial number indicate the year, and the fifth placeholder is a letter the represents the month.  (A=January…)

Luxaire (See “York”)

Nordine (Gibson)

Nordine uses several codes.  The first method is the fourth and fifth placeholders in the serial number is the year, and the sixth and seventh place holders are the month (***YYMM).

The second method uses the numerals in the third and forth placeholders for the year (**YY).

Payne (See “Bryant”)

Rheem and Ruud

In the middle of the serial number will the letter “F” or “M”, the following four numbers are the week and the year.  (“F”WWYY) or (“M”WWYY)

York (The York family include Coleman, Evcon, Frasier-Johnson, Luxaire, and Unitary)

This family of manufacturers uses several methods of using including date codes in the serial number.  One method is the first two number in the serial number are year, the next two numbers are the month (YYMM).

Another method to identify the year of manufacture of some Luxaire and York furnaces by using letters in the second and third placeholders of the serial numbers.  These serial numbers are easy to identify as they start with four letters.  A=1971 or 1992, B=1972 or 1993, C=1973 or 1994, D=1974 or 1995, E=1975 or 1996, F=1976 or 1997, G=1977 or 1998, H=1978 or 1999, J=1979 or 2000, K=1980 or 2001, L=1981 or 2002, M=1982 or 2003, N=1983 or 2004, P=1984, R=1985, S=1986, T=1987, V=1988, W=1989, X=1990, Y=1991.

A second method uses the third placeholder, a letter, in the serial number to identify the production code.
X=1990, Y=1991, A=1992, B=1993, C=1994, D=1995, E=1996, F=1997, G=1998, H=1999,
J=2000, K=2001, L=2002, M=2003, N=2004, P=2005.

For 2006 and after, the second and the fourth placeholders are numerals that when combined, indicate the year.

The following are brands of boilers commonly found in southeast Michigan.  This list is not all encompassing, and mistakes are bound to happen.  A contentious effort was made to provide the correct information to assist in determining the age of the boiler, but due to the numerous manufactures and the variations of dating codes, no liability can be assumed.

Bryant

For Bryant boiler manufactured form 1985 to the present, the date code is embedded in the first four placeholders of the serial number.  Either the first four digits in the serial number is the week and year (WWYY), or the first two four digits are the year and month (YYMM).

Bryant boilers manufactured from 1980 to 1984, an 8-digit serial number was used with the first letter signifying the month (M=January…Z=December) and the numeral in the second position (1 through 4) represents the year.

Bryant boilers manufactured from 1970 to 1979, a 7-digit serial number was used.  The first letter of the serial number signifies the month (A=January…L=December), and the second placeholder is a number signifying the year.  (0=1970, 9=1979).

Burnham

Newer Burnham boilers have the date of manufacture listed in the upper right-hand corner of the data sticker.  Older Burnham boilers have a Byzantine age code.  Look for the ANSI date and a couple of years to get a rough approximation of the age.

Lochinvar

Lochinvar boilers manufactured in 1993 through 2012, the first placeholder in the serial number is the production year.  (1993=K, 1994=L, 1995=M, 1996=N, 1997=p, 1998=S, 1999=T, 2000=W, 2001=X, 2002=Y, 2003=Z, 2004=A, 2005=B,2006=C, 2007=D, 2008=E, 2009=F, 2010=G, 2011=H, 2012=J, 2013=K.)

Lochinvar has also used the first two digits of the serial number for the year, and the next two digits for the week (YYWW).

Peerless

Beginning in 2000, the first set of numbers is the sequence number, the set of numbers after the dash is the year and month (-YYYYMM)

Between 1984 and 1999, the set of numbers after the dash were the month and year of manufacture (MMYY).

Teledyne Laars

The first digit or letter in the serial number represents the month, and the next two digits represent the production year (MYY).

Weil-McLain

Weil-McLain assigns a serial number to each boiler.  The serial number prefix is “CP” followed by the actual serial number.  The following chart can be used to date the boiler by the serial number:

1988 141001 to 1681500
1989 1681501 1871500
1990 1871501 2056000
1991 2056001 2217391
1992 2217400 2399999
1993 2400000 2609500
1994 2609501 2815000
1995 2815001 3003000
1996 3003001 3213000
1997 3213001 3441400
1998 3441401 3621000
1999 3621001 3810000
2000 3810001 4055000
2001 4055001 4311000
2002 4311001 4586999
2003 4587000 4807000
2004 4807001 5047000
2005 5047001 5301000
2006 5301001 5454497
2007 5454498 5731063
2008 5731064 5957346
2009 5957347 6150483
2010 6150484 6368018
2011 6368019 6555277
2012 6555278 7779489
2013 7779490

Utica

  • Prior to 1979; the first two digits is the month, and the third and forth digits are the year.  For example, 12-63 is interpreted as December of 1963.
  • For years 1979 through 2002, the first letter in the serial number is the code for the month, and the second letter is the code for the year.  See below.
  • For years 2003 and after, all serial number begin with the letter “U”, the second letter is code for the month, and the third letter is code for the year.

A for January through L for December

J 1980

K 1981
L 1982
M 1983
A 1984
B 1985
C 1986
D 1987
E 1988
F 1989
G 1990
H 1991
N 1992
P 1993
R 1994
S 1995
T 1996
U 1997
V 1998
W 1999
9 Jan thru Aug 2000
X Sept thru Dec 2000
Y 2001
Z 2002
U_A 2003
U_B 2004
U_C 2005
U_D 2006
U_E 2007
U_F 2008
U_G 2009
U_H 2010
U_I 2011
U_J 2012
U_K 2013

The following are brands of water heaters commonly found in southeast Michigan.  This list is not all encompassing, and mistakes are bound to happen.  A contentious effort was made to provide the correct information to assist in determining the age of the water heater, but due to the numerous manufactures and the variations of dating codes, no liability can be assumed.

First when dating a water heater, first look at the data tag, the manufacturing date may be displayed on the label.

Second, look for the serial number.  Sometimes the date is hidden within the serial number.  For example, C12 could indicate that the water heater was constructed in March of 2012.  Also look around the serial number.  Sometimes a key for understanding the date code is present.

Third, if the date of manufacture is not immediately evident, a little sleuthing around the label may not reveal the date of manufacture, but a window of time the water heater was constructed in.  Look at the lower portions of the data sticker for the letters “ANSI Z” or “CSA”.  There is usually a year in four digits after these letters.  The year represents the code or standards to which the water heater was constructed.  For example, the if the “ANSI-Z” year is 2006, the water heater was likely constructed during a six year window from 2007 through 2012.

Finally, if all else fails, look for the brand and the serial number and use the charts below:

American (also Champion, Craftmaster, Ace, Tru-Test, Whirlpool, U.S.)

The first two digits in the serial number represent the year, the next two digits represent the week of manufacture.  For example, 0732 indicated that the water heater was constructed in 2007, the 32 week.

A. O. Smith

Prior to 2008, AO Smith used the second letter as the month code followed by 2-digits which represent the year.  For example, F08 is the sixth month of 2008.  (The letter “I” is skipped as it looks too much like a “1”.)

After 2008, AO Smith the first two digits in the serial number are the year followed by two more for the week.  For example, 0806 is the sixth week of 2008.

Bradford -White (also Lochinvar)

Year (first digit) Month (second digit)
G 1990 A January
H 1991 B February
J 1992 C March
K 1993 D April
L 1994 E May
M 1995 F June
N 1996 G July
P 1997 H August
S 1998 J September
T 1999 K October
W 2000 L November
X 2001 M December
Y 2002
Z 2003
A 2004
B 2005
C 2006
D 2007
E 2008
F 2009
G 2010
H 2011
J 2012
K 2013
L 2014

Rheem (Lowe’s, Ruud)

Rheem uses a 2-digit month followed by a 2-digit year.  For example, 0608 represents the sixth month followed by the year.  Or June of 2008.

State (Ace, Barnett, Kenmore, Richmond)

Before 2008, State used a 1-letter month followed by a two-digit year.

For 2008 and after, use A. O. Smith’s code.  State was acquired by AO Smith and uses Smith’s code.  The first two digits in the serial number are the year followed by two more for the week.  For example, 0806 is the sixth week of 2008.