Takagi Water Heater Age Checker
Decode your Takagi serial number to find the manufacturing date, age, and full specs. Free and instant - no account needed.
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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 water heaters represent Japanese engineering excellence and innovation in tankless water heating technology. Founded in 1946 in Fuji City, Japan, Takagi Industrial Co. has been a pioneer in developing on-demand water heating systems. The company entered the North American market in 1998 and has established itself as a trusted name among professional contractors and homeowners seeking reliable, energy-efficient hot water solutions.
Takagi manufactures a comprehensive range of tankless water heaters for residential and commercial applications. Their T-H3 series offers high-efficiency condensing performance with up to 0.95 UEF ratings, while the T-K4 series provides compact solutions for smaller spaces. All models feature advanced temperature control and modulating gas valves for precise hot water delivery. Takagi backs its products with up to 15-year heat exchanger warranties on residential units. For units made 2009 and later, serial numbers use a YYWW format where the first two digits indicate the year and the next two digits indicate the week of manufacture. For older units (pre-2009) with 8-digit sequential serial numbers, please contact Takagi directly at 888.882.5244 to determine the manufacturing date.
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 digits and doesn't look like a date code - how old is it?
Takagi units made before 2009 used a purely sequential 8-digit serial with no embedded date code. To get the manufacturing date you need to call Takagi tech support at 888-882-5244 with the serial - they can look up the production batch and quote the date. Any unit with that format is at least 15 years old by now.
Is Takagi the same company as A.O. Smith?
Takagi was acquired by A.O. Smith in 2009, so post-2009 units are essentially A.O. Smith products with the Takagi brand. The Japanese R&D and design heritage continues, but distribution, warranty, and service now run through the A.O. Smith network in North America.
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.
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