Takagi Tankless Water Heaters
Tankless water heaters were once the wave of the future, but now they are gaining in popularity every day as homeowners and business owners alike discover the benefits of instant water heating technology. Takagi is a leader in the industry and is known as one of the best tankless water heaters. PlumbingSupply.com® is your source for Takagi tankless gas water heaters -save on your water heating bills, and save the environment!
Takagi Tankless Water Heater Information
Comparison Chart
| Model |
Max BTU
(NG) |
Min BTU
(NG) |
Flow Rate
(GPM) |
1st Hour
Rating |
Energy
Factor |
Thermal
Efficiency |
Net
Weight |
Dimensions
(H x W x D)" |
TK-110U
Indoor or Outdoor |
140,000 |
19.500 |
0.75 - 6.6 |
180 gal/hr
(77°F rise) |
NG: 0.81
LP: 0.81 |
NG: 81%
LP: 81% |
37-1/2 lbs |
20-1/2" x 13-3/4" x 9-1/2" |
TK-310U
Indoor or Outdoor |
190,000 |
19,500 |
0.50 - 8.0 |
246 gal/hr
(77°F rise) |
NG: 0.82
LP: 0.82 |
NG: 82%
LP: 82% |
48 lbs |
20-1/2" x 13-13/16" x 9-1/2" |
TK-510U
Indoor or Outdoor |
199,000 |
19,500 |
0.50 - 10.0 |
252 gal/hr
(77°F rise) |
NG: 0.82
LP: 0.82 |
NG: 82%
LP: 82% |
39 lbs |
20-1/2" x 13-13/16" x 8-1/2" |
TH-3-DV
Indoor |
199,000 |
15,000 |
0.50 - 10.0 |
252 gal/hr
(77°F rise) |
NG: 0.93
LP: 0.93 |
NG: 95%
LP: 95% |
59 lbs |
22-1/2" x 17-3/4" x 10-3/4" |
Flow Rate Guide (Temp Rise vs GPM)
| Temperature Rise (F°) |
| Model |
35 |
40 |
45 |
50 |
55 |
60 |
65 |
70 |
75 |
80 |
85 |
90 |
95 |
100 |
105 |
110 |
| TK-110U Indoor or Outdoor |
6.6 |
6.6 |
5.7 |
5.1 |
4.6 |
4.2 |
3.8 |
3.5 |
3.3 |
3.1 |
2.9 |
2.7 |
2.4 |
2.3 |
2.2 |
2.1 |
| TK-310U Indoor or Outdoor |
8.0 |
7.8 |
6.9 |
6.2 |
5.7 |
5.4 |
4.8 |
4.4 |
4.1 |
3.9 |
3.7 |
3.5 |
3.3 |
3.1 |
3.0 |
2.8 |
| TK-510U Indoor or Outdoor |
9.0 |
9.0 |
8.1 |
7.3 |
6.7 |
6.1 |
5.6 |
5.6 |
5.2 |
4.9 |
4.6 |
4.3 |
4.0 |
3.7 |
3.4 |
3.1 |
| TH-3-DV Indoor |
10.0 |
9.5 |
8.4 |
7.6 |
6.9 |
6.3 |
5.8 |
5.4 |
5.0 |
4.7 |
4.4 |
4.2 |
4.0 |
3.8 |
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Quick Installation Check List
Knowing what you need to do when you are deciding whether to buy a tankless water heater or not can help save you money!
| Category |
Sub-Category |
Description |
| Electrical |
Voltage |
120 VAC electrical ground all the way back to electrical service panel |
| Water |
Pressure |
A steady 40 - 60 PSI for maximum flow |
| Quality |
Hard water must be treated with softener or conditioner |
| Well Water |
Water pressure must be checked & mineral contents treated |
| Pipe Material |
No galvanized supply water pipe |
| Valves |
Pressure relief only, no T&P |
Recirculation
Line |
Recirculation lines should go through a small electric water heater and not directly back through the Takagi tankless water heater |
| Gas |
Gas Type |
Factory Set For Natural Gas And Includes Liquid Propane Conversion Kit |
| Pipe Size |
Minimum 3/4" I. D. (inside diameter) |
| Pressure (NG) |
4.0 - 10.0 WC (water column inches) (7.0 WC ideally) |
| Pressure (LP) |
8.0 - 14.0 WC (water column inches) (10.0 WC ideally) |
| Air |
Material |
Exhaust: 4" stainless steel, cat III
Intake: 3" any material - seal connection |
| Layout |
4" exhaust must be individually run per unit all the way to outside
No common venting
No increase or decrease in diameter |
| Venting Length |
25 - 60ft depending on unit - Deduct 5ft for each elbow used in the venting |
| Condensation |
Must have condensation drain when linier run exceeds more than 5ft to protect heat exchanger |
Combustion
Air Supply |
Air supply from outside: 1sq. Inch / 15,000 BTU
Air supply from inside: 1sq. Inch / 1,000 BTU |
How Takagi Tankless Water Heaters Work
Takagi Tankless Water Heater Single Unit Recirculation Example
Takagi Tankless Water Heater Multi Unit Recirculation Example
Frequently Asked Questions
Q. "What type of vent do these tankless water heaters require?"
A. These tankless water heaters require Category III stainless steel vent only.
Q. "I've heard that some Takagi tankless water heaters cannot be installed in a few areas. Is that true?"
A. Yes, there are some counties that do not allow for the installation of a few Takagi tankless water heaters. For this reason, the person purchasing one of the following models is responsible for checking with their local code authorities prior to ordering: T-M32-NG, T-D2-IN-NG, T-D2-OS-NG, T-K4-IN-NG, T-K4-OS-NG, T-KJr-IN-NG, T-KJr-OS-NG. Here's a list (not complete) of some California counties that do not allow these water heaters to be installed: Sacramento, Yolo, Sonoma, San Joaquin, Napa, Marin, Solano, Contra Costa, San Francisco, San Mateo, Alameda, and Santa Clara. Again, this list is not complete, so it's up to the purchaser to check with local code authorities prior to ordering.
All Takagi Tankless Water Heaters must be installed by a licensed professional.
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