John Wood® Water Heaters
The date of production/manufacture or age of John Wood® Water Heater(s) can be determined from the serial number.
Serial number styles/formats found are:
Style 1 (before 2008): U0106413635
Style 2 (after 2008): U0928413635
Style 3 (old style): 137945-7503
Style 4 (used between styles 1 & 3): 8711-127684
See Also: GSW™ Water Heaters and AO Smith Water Heaters
John Woods and GSW water heaters were acquired by State Industries/AO Smith in 2006
Style 1: U0106413635
John Wood serial numbers contain a lot of information, including when the heater was manufactured. This can be determined by looking at the first four numbers, ignoring any letter that may start the serial number. Similar to style 2 below with exception that month was used rather than week.
The first two numbers represent the year the water heater was built.
If your heater was built before 2008, the next two numbers represent the month.
If your heater was built after 2008, the next two numbers represent the week.
For Example
Serial number: U0106413635
This heater was manufactured in June 2001
Style 2: U0928413635
John Wood serial numbers contain a lot of information, including when the heater was manufactured. This can be determined by looking at the first four numbers, ignoring any letter that may start the serial number. Similar to style 1 above, with exception that week was used rather than month of manufacture.
The first two numbers represent the year the water heater was built.
If your heater was built before 2008, the next two numbers represent the month.
If your heater was built after 2008, the next two numbers represent the week.
For Example
Serial number: U0928413635
This heater was manufactured in the 28th week (July), 2009.
Style 3: 137945-7503
This is an older John Wood serial number style (prior to 2006 A.O. Smith acquisition of GSW and John Wood brands). The manufacture date can be determined by looking at the last four numbers after the hyphen in the serial number.
The first set of these numbers (after hyphen) represent the year the water heater was built.
The next (last) two numbers (after hyphen) represent the month.
For Example
Serial number: 137945-7503
This heater was manufactured in the 3rd month (March), 1975.
Style 4: 8711-127684
This is an older John Wood serial number style (prior to 2006 A.O. Smith acquisition of GSW and John Wood brands and possibly used between styles 1 and 3). The manufacture date can be determined by looking at the first four numbers before the hyphen in the serial number.
The first two numbers (before hyphen) represent the year the water heater was built.
The next (last) two numbers (before hyphen) represent the month.
For Example
Serial number: 8711-127684
This heater was manufactured in the 11th month (November), 1987.
Every effort is undertaken to offer you correct and concise information to assist you in determining the age or manufacture date of water heating equipment. Anytime anyone is dealing with numbers and letters in determining data, mistakes and misinterpretation are bound to happen. For this reason if you find during your research that we may have erred please contact us. In addition perhaps you have come across a brand, model or serial number format that we have not addressed. Contact us with your concerns or new submissions. Please include all pertinent information including clear and legible pictures of data/nomenclature plates.
