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T-D2-IN Takagi Tankless Indoor Water Heater (Natural Gas)
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T-D2-IN-NG has been discontinued
Discontinued July 23, 2019
This product was discontinued by the manufacturer.
MANUALS (4)
This item replaces: T-K3-PRO-NG
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Direct Replacement:
Series 200 Ultra Low-NOx Non-Condensing Indoor Tankless Water Heater (10 GPM, NG/LP)
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Product Highlights
–
Natural Gas
10 MAX GPM
Indoor Only
99°F - 176°F
Direct Vent Convertible
20.3"
Description
–
The Takagi brand has been discontinued by the manufacturer as of December 31, 2025. Suggested replacement units will be available on our website and replacement parts will continue to be available as supplies last. If you'd like any further assistance, please contact our customer service team.
Think Green, Save Green. Rebate and incentive programs provide cash-back to consumers for the purchase of appliances that meet certain energy efficiency standards. Most states are offering rebates in the $50 to $250 range. You can search for rebates in your area from here.
Note: Isolation valves are not included but are recommended for installation.
The NEW T-D2-IN/OS model was specifically designed for light commercial applications, including small restaurants and beauty salons. The T-D2-IN/OS offers all the features of the "Revolutionary T-K3-Pro" model and now has an outside specific model along with a max flow rate of 10.0GPM.
Utilizing HRS35 copper alloy for the heat exchanger tubing, the T-D2-IN/OS is also suited for heavier-residential usages such as space-heating and domestic recirculation systems. The TM-RE30 is included with T-D2-IN and T-D2-OS
TM-RE30 Remote Control is included:
Specifications:
- Flow Rate: Maximum 10.0 GPM
- Gas Inputs: 11,000 to 199,000 BTU per hour
- Energy Factor Rating: 0.83
- Inlet Gas Pressure: Min: 5.0" W.C. / Max 10.5" W.C.
- Dimensions: 20.3" H x 13.8" W x 8.5" D
- Direct Vent Capability
- Electric Ignition
Specs
–
| Application: | 2-4 Showers |
|---|---|
| Product Type: | Tankless Heater |
| Venting Requirement: | Category III Stainless Steel |
| Fuel Type: | Natural Gas |
| Vent Type: | Direct Vent Convertible |
| Installation Type: | Indoor Only |
| Height: | 20.3" |
| Energy Factor: | 0.83 |
| Width: | 13.8" |
| Vent Size: | 4" |
| Depth (Inches): | 8-1/2" 9-1/2" |
| BTU (Min): | 11000 |
| BTU (Max): | 199000 |
| Max Flow (GPM): | 10 |
| Inlet Gas Pressure: | 5.0-10.5"W.C. |
| Voltage: | 120v |
| Manifold Pressure: | 2.0-2.5"W.C. |
| Energy Star Rated: | No |
| Gas Input: | 11000-199000 BTU/h |
| Height (Inches): | 20.25" |
| Water Connection: | 3/4" |
| Width (Inches): | 13-3/4" |
| Gas Connection: | 3/4" |
| Temperature Range (F): | 99°F - 176°F |
| PSI Range: | 15-150 psi |
| Weight (lbs): | 39 lbs |
Questions?
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Call or text 888-757-4774
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Friday
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Saturday – Sunday
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Compare Similar Products
Brand
Application
Product Type
Venting Requirement
Fuel Type
Vent Type
CURRENT ITEM
2-4 Showers
Tankless Heater
Category III Stainless Steel
Natural Gas
Direct Vent Convertible
You May Also Need
83 Replacement Parts
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AO SmithInlet Water Filter, 100074382
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TakagiOutlet Drain Plug, 100074383
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AO SmithFlame Rod, 100074220
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TakagiKit, Ring, Silicon, 100074390
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AO Smith
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Product Reviews
4.9 out of 30 reviews
100% would recommend this product
5 star
90%
4 star
10%
3 star
0%
2 star
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1 star
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Customer Images
Showing 1-10 of 30 reviews
More please
Another Takagi. The first Takagi lasted over 16 years. (Time flies when you're enjoying hot showers!) So, back for more of the same. The current model is a bit smaller physically, has gas & plumbing connections in a different location, is advertised to heat a little more hot water, and surprisingly cost about the same as the one purchased over 16 years ago. Working flawlessly. The old heater required a trip to the basement to reset it after a power outage; the new one resets itself and retains the temperature setting!
Arrived well-packed. Prompt shipping. Thanks guys!
MT
Cleveland, OH
7 years ago
Verified Buyer
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Perfect replacement for an older Takagi
I had an older Takagi TM-1 that died after 15 years. I was looking for a replacement and was steered toward another Takagi model that is used in my area that is a lot more expensive and required more exhaust modifications. The T-D2-IN required very little plumbing modifications and is working perfectly for just about the same price as a good tank water heater. This was a no brainer for me.
Albert Kock
CA
7 years ago
Verified Buyer
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JUST WHAT I NEEDED AND WAS HERE THE NEXT DAY
USE IT AT A LAKE HOUSE THAT WE HAVE
RON
STURGIS MI
7 years ago
Verified Buyer
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Great hot water heater. No complaints what so ever
Had the same exact unit for approximately 15 years, lived its life to the fullest. Great product so much that I bought the same one again. pretty efficient, I have 4 bathrooms, family of 7 and never ran out of hot water
Danny
Pawtucket, RI
7 years ago
Verified Buyer
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Great Water Heater but
This is a non condensing water heater. If you are going though a combustible wall you will need to install the sill plate. The exhaust pipe for this unit will be 350-400 degrees during operation. If I knew that I would of got a condensing water heater instead. But this water heater is a beast!!
Jonny B Good
Michigan
8 years ago
Verified Buyer
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Hot showers!
We previously had a tank waterheater and with three daughters I was always getting in at the end of the night with no more hot water. I love that this provides an unending supply of hot water! You can hear it kick on right away when you turn on the hot faucet. I love that it has a digital interface for changing the water temp. It allows us to keep it away from scalding temps easily since we have little ones. Provides enough hot water for dish washer, washing machine, and two showers going at once. Very happy with my purchase!
Taximom
Phoenix, AZ
8 years ago
Verified Buyer
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Great service with overnite delivery.
Replaced my old tankless, this works fine and has added thermostat settings which are easy to use. No problem with installation and unit worked immediately. Best part of deal was the rapid response from SupplyHouse.
John
Braintree, MA
8 years ago
Verified Buyer
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Replacing T-K3 after 10 years of Service
We use this product to heat our domestic hot water and our home through an air to water heat exchanger. There was never a problem supplying enough hot water to do both tasks.
Unit worked flawlessly for 10+ years until it began to leak this spring.
Mike
Southwest Pennsylavania
8 years ago
Verified Buyer
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First tankless and very pleased
My house had 2- 40gal traditional hot water heaters and I was really nervous that going tankless would have limitations for hot water on demand. My house has 5 bathrooms and we are a family of 4. Once it was installed I was able to turn on multiple showers simultaneously and had zero issues with it keeping up with demand. The only issue I had was when I installed it I used a flex gas line to make the final connection. That was restricting the flow and the unit keeps turning off as a result. I switched that to hard pipe and the problem went away. Also, the gas line near where I installed it is only 1/2" and the manual recommends 3/4". This combined with the flex gas line could have been my issue but once I used hard pipe everything worked great. It does take about 10-15 seconds longer to produce hot water at the fixture. It is very quiet as well.
Dave
Marlboro,NJ
8 years ago
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I will by this product again for my shop
Good product and the great service with very competitive prices. Ordered in the afternoon and was at my door the next day.
D. Wyse
Archbold, Ohio
9 years ago
Verified Buyer
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Product Q&A
10 Questions10 Questions
Q: Is there a propane conversion option for this product?
Asked by Dave 11 years ago
Add your answer
Verified Reply- SupplyHouse StaffNo, the unit cannot be converted to propane.
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Q: What other accessories I need to get with this unit? Vent, pipes and etc.
Asked by wondering 12 years ago
Add your answer
Verified Reply- Supplyhouse StaffVenting would most likely be needed as well as piping, it would be impossible to give you a complete materials list as that is dependent on field conditions and existing equipment & piping.
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Q: Can it cascading with extra units?
Asked by wondering 12 years ago
Add your answer
Verified Reply- Supplyhouse Staffyes you can see page 24. http://s3.supplyhouse.com/manuals/1289421060124/41440_PROD_FILE.pdf
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Q: Can the vent tap on to the chimney?
Asked by wondering 12 years ago
Add your answer
Verified Reply- Supplyhouse Staffno it can not.
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Q: I have 2 showers,1 washing machine, and a jacuzzi tub. Could you help me narrow down the best option for a tankless water heater? I have propane (LP). Also,what is better direct vent or PVC horizontal venting? Thanks, Lance
Asked by Lance 13 years ago
Add your answer
-
I have 3 showers, washing machine, dishwasher and a 2 person jacuzzi tub. I have never run out of hot water with this unit. I don't think u can use PVC venting for this unit. It requires double wall stainless pipe, at least that's what I was told and used. Sent from my iPad
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- Digger
T-D2 Takagi tankless water is more than big enough for your needs. Direct vent will have to be used not the PVC pipe
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Q: Can it be used for radiant heat
Asked by Juggy Gales 13 years ago
Add your answer
Verified Reply- PexSupply StaffThis heater can be used for radiant heating, but make sure to use primary/secondary piping. We would also recommend a heat exchanger is you plan to use the same heater for radiant heating and domestic water heating.
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-
Yes, as long as it is for radiant only, can't mix radiant (dirty water) with drinking or washing water. Sent from my iPad
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- kpkwshaw
I am using 2 of the natural gas version for radiant in concrete floor heat. Been about 2 years, been great Kelly
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Q: what is the maximum horizontal venting distance on the 4 inch vent
Asked by 15 years ago
Add your answer
Verified Reply- PexSupply StaffPlease refer to the manual linked below for venting instructions and specifications. http://s3.pexsupply.com/manuals/1289421060124/41440_PROD_FILE.pdf
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Q: what is the head loss caused by this unit at 8 gpm (for use in a hydronic heating system)
Asked by off grid 15 years ago
Add your answer
Verified Reply- PexSupply StaffThe head loss is 54.6.
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Q: 1600 square feet 80000btu load 1bath about 40gallons domestic hot water per day will this unit handle it
Asked by joe 15 years ago
Add your answer
Verified Reply- PexSupply StaffFor a 80,000 BTU heating load, this unit would need to produce 8 GPM. Please refer to the specifications linked below to see the pressure drop of this unit for your project. http://s3.pexsupply.com/manuals/1289487577449/41590_PROD_FILE.pdf
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Q: is this suitable for 2400 sq ft home baseboard heat and 2bath
Asked by bob 15 years ago
Add your answer
Verified Reply- PexSupply StaffIt depends on the BTU load and water usage of your home. This unit can handle up to 10 gallons per minute.
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