Takagi Water Heater Age Lookup
Takagi builds rugged tankless heaters across the T-K, T-H, and T-D series. Drop in your serial number to find the manufacturing date and how old your unit is. Free and instant - no login.
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Finding Your Takagi Serial Number
Check these four spots on your Takagi water heater
Common Locations
What to Look For
- White or metallic manufacturer sticker
- Labeled "Serial No." or "S/N"
- Typically 8–12 characters long
- Usually near the model number
Can't find it? Try removing access panels or checking behind the temperature dial.
Takagi Serial Number Examples
Don't worry if yours looks different - Takagi has multiple formats and our system can decode most variations.
About Takagi Water Heaters
Takagi Industrial started in Fuji City, Japan in 1946 and was among the first companies to bring tankless water heating to the United States, arriving in 1998 with a base in Irvine, California. In 2006 it formed a tankless joint venture with A.O. Smith, and Takagi now sits within the A.O. Smith group, which is where warranty and parts support runs.
The line is gas tankless for residential and commercial use. The T-H3 condensing series reaches about 0.95 UEF, while the T-K and T-D families cover smaller and mid sized loads. Residential heat exchanger coverage runs up to 15 years.
Dating depends on the era. Units from 2009 onward use the two digit year followed by the production week, so a serial starting 1522 is week 22 of 2015, either with a letter after the week or as a 13 digit all-number serial. Short serials of just eight or nine digits are a different style: a model code plus a plain sequence number, with no date encoded in it at all. Units built before 2009 carry this style, and so do some later models. Those have to be looked up by hand, and Takagi will do it at 888.882.5244.
Where to find the serial
Takagi tankless units have the rating plate on the right side of the cabinet. The serial is in a tall black bordered box and is labeled SER. NO. or S/N. Takagi is owned by A.O. Smith now, so newer units may also carry an A.O. Smith stamp on the documentation.
What the serial actually looks like
Why the age is worth knowing
Takagi residential tankless units come with 15-year heat exchanger warranties on the T-H3 condensing models and 10 to 12 years on non-condensing T-K series. The most common failure is the bottom heat exchanger cracking from thermal cycling after 8 to 12 years of hard use, which is usually a replacement-rather-than-repair situation.
Quick answers for this brand
My Takagi serial is 8 or 9 digits and doesn't look like a date code - how old is it?
Short Takagi serials of 8 or 9 digits are a model code plus a plain sequence number, with no embedded date code. Takagi used this style on units made before 2009 and on some later models, so the serial alone can't date the heater. Check the rating plate for the ANSI or CSA approval year (the heater was built in or after that year), or call Takagi tech support at 888-882-5244 with the serial and they can look up the production date.
Is Takagi the same company as A.O. Smith?
Takagi, founded in 1946 in Fuji City, Japan, formed a tankless joint venture with A.O. Smith in 2006 and now sits within the A.O. Smith group. The Japanese R&D and design heritage continues, but distribution, warranty, and service run through the A.O. Smith network in North America, with the US base in Irvine, California.
Why does my Takagi throw error code 11 or 14?
Code 11 is no ignition (gas, igniter, or flame rod issue) and code 14 is overheat shutdown (usually scale buildup or restricted exhaust). Both can be triggered by maintenance neglect rather than age. Descale annually, clean the inlet filter, and check the venting for blockages before assuming the unit is dying.
Need a plumber?
Tell us about the job and get matched with licensed pros in your area.
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Share this tool with friends!
Know someone with an aging water heater? Send them a free check.