Takagi T-D2-OS-N
The Takagi T-D2-OS-N is a non-condensing tankless water heater — a DHW-only appliance, not a boiler — firing 11,000 to 199,000 BTU/h on natural gas with 0.8% thermal efficiency and up to 10 GPM.
Key figures
- Max input
- 199,000 BTU/h
- Max CSA output
- —
- AFUE
- —
- Min input
- 11,000 BTU/h
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Takagi T-D2-OS-N in practice
The T-D2-OS-N is the natural gas outdoor model in Takagi's T-D2 tankless water heater family. Takagi — T-KJr2/T-K4/T-D2 Specification Sheet (TRGSS01613) prints an input range of 11,000 to 199,000 BTU/h with 0.8% thermal efficiency, up to 10 GPM maximum flow, 3/4" NPT water connections and a 3/4" NPT gas connection.
The unit measures 20-1/4 × 13-3/4 × 9-1/2 in and weighs 45 lb, and it is installed outdoors. Integral exhaust vent on the front of the outdoor unit. It is a tankless water heater, not a boiler: Takagi's catalogue contains no boiler line, and where the family is used with storage tanks, recirculation or combined domestic & heating applications, the appliance remains a water heater whose installation and system design follow the official manual and local code.
No Canadian availability statement appears on the captured pages, so Canadian availability is recorded as unknown. Sizing, venting design and gas-supply capacity are engineering decisions for a licensed contractor following the current installation manual.
Best suited to
- Outdoor domestic hot-water service at up to 199,000 BTU/h input
- Projects needing 0.8% thermal efficiency operation with up to 10 GPM
- Residential systems that can manifold units for additional capacity
Applicability and support
- Model number
- T-D2-OS-N
- Canadian availability
- unknown
- Production status
- current
- ROMA supplies
- Confirmed at consultation
- ROMA services
- Confirmed at consultation
- Warranty
- Not verified
Where ROMA provides on-site service
On-site service is currently offered in Greater Vancouver, BC, including Vancouver, Burnaby, Richmond, Surrey, Coquitlam, North Vancouver, West Vancouver, New Westminster, Port Coquitlam, Port Moody, Delta, Langley, Maple Ridge, Abbotsford, Chilliwack, White Rock, Pitt Meadows, Tsawwassen, Anmore, Lions Bay, Belcarra, Bowen Island, Mission. Everything else on this site is reference information you can use anywhere in Canada.
Specifications
Published specifications
Values as published by Takagi. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Input, maximum | 199,000 BTU/h | As printed in Takagi — T-KJr2/T-K4/T-D2 Specification Sheet (TRGSS01613). |
| Input, minimum | 11,000 BTU/h | As printed in Takagi — T-KJr2/T-K4/T-D2 Specification Sheet (TRGSS01613). |
| Efficiency | ||
| Thermal efficiency | 0.8 % | As printed in Takagi — T-KJr2/T-K4/T-D2 Specification Sheet (TRGSS01613). |
| Domestic hot water | ||
| Maximum flow rate | 10 GPM | Factory-tested maximum; 0.4 GPM required for continuous fire after ignition (0.5 GPM activation on commercial sheets). |
| Venting and air | ||
| Venting | Integral exhaust vent on the front of the outdoor unit | |
| Physical and connections | ||
| Hot/cold water connections | 3/4" NPT | |
| Gas connection | 3/4" NPT | |
| Dimensions (H × W × D) | 20-1/4 × 13-3/4 × 9-1/2 in | |
| Weight | 45 lb | As printed in the specification sheet. |
| Operating limits and other | ||
| Installation | Outdoor | |
| Technology | Non-condensing tankless water heater | |
| Manifold capability | Easy-Link with up to three other T-H3 units; common vent up to 8 units | As printed in the specification sheet. |
Manuals
Frequently asked questions
Is the Takagi T-D2-OS-N a boiler?
No. It is a tankless water heater (DHW-only). Takagi's catalogue contains no boiler line; where the family is used with hydronic or radiant systems, the appliance is still a water heater and the system must be designed by a licensed contractor.
What is the input range of the T-D2-OS-N?
Takagi — T-KJr2/T-K4/T-D2 Specification Sheet (TRGSS01613) prints 11,000 BTU/h minimum and 199,000 BTU/h maximum input on natural gas, with up to 10 GPM and 0.8% thermal efficiency.
Where can I find the official documentation for the T-D2-OS-N?
The specification sheet TRGSS01613 is served from takagi.com (https://www.takagi.com/media/19489/TRGSS01613.pdf), and the product page https://www.takagi.com/products/tankless-water-heaters/t-d2-os-n lists the installation and owner's manuals.
Questions about the Takagi T-D2-OS-N?
Describe what the boiler is doing and get a straight answer about the next step.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
- Takagi — T-KJr2/T-K4/T-D2 Specification Sheet · TRGSS01613 · accessed September 9, 2026
- Takagi — T-D2-OS-N product page · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.