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199,000 BTU ATO-510 Non-Condensing Ultra-Low NOx Outdoor Tankless Water Heater (NG/LP)
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ATO-510-U has been discontinued
Discontinued October 2, 2026
This product was discontinued by the manufacturer.
MANUALS (3)
This item replaces: ATO-510U-200, ATO-510-N
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Product Highlights
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Natural Gas, Propane
10 MAX GPM
Outdoor Only
120v
9-1/2" Depth
20.5" Height
Description
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This unit is NOT approved for installation in Manufacture Homes and is not suitable for space heating applications only.
The 510U is well suited for residential/commercial applications such as small restaurants and beauty salons. It features a commercial grade copper heat exchanger with a thicker heat exchanger drum which is suitable for commercial applications or heavier-residential usages such as space heating or domestic recirculation systems. The design allows for a variety of installation options. Complies with Ultra-Low NOx regulations and meets the energy efficiency requirements of ASHRAE 90.1-b 1992. Easy-Link System capable up to 4 units. Multi-Link system capable up to 20 units. The ATO-510U-N tankless water heater uses up to 199,000 BTUs of natural gas to deliver a max flow rate of 10 GPM. It utilizes non-condensing technology to achieve an Energy Factor of 0.82. This model meets Ultra-Low NOx emission requirements, and comes with a 15-year limited warranty. A. O. Smith's ProLine water heaters are residential products built to commercial-grade standards and are only available for purchase through professional wholesalers and contractors.
Features:Continuous flow rate up to 10.0 GPM Wall-mount design saves valuable space and allows for additional storage and flexibility Commercial-grade copper heat exchanger is 25x better than stainless steel at heat transfer, stabilizing outgoing water temperatures quicker Easily convertible from natural gas to propane with supplied kit Highly efficient condensing Ultra-Low Nox tankless water heater delivers up to .81 Uniform Energy Factor (UEF) Vents up to 60 feet using 4” Category III Stainless Steel Includes a wall mount temperature remote controller and advanced diagnostics to simplify troubleshooting Safety features include built-in freeze protection, overheat cut-off fuse and air-fuel ratio (AFR) sensor 15-year limited warranty on heat exchanger in residential applications
The 510U is well suited for residential/commercial applications such as small restaurants and beauty salons. It features a commercial grade copper heat exchanger with a thicker heat exchanger drum which is suitable for commercial applications or heavier-residential usages such as space heating or domestic recirculation systems. The design allows for a variety of installation options. Complies with Ultra-Low NOx regulations and meets the energy efficiency requirements of ASHRAE 90.1-b 1992. Easy-Link System capable up to 4 units. Multi-Link system capable up to 20 units. The ATO-510U-N tankless water heater uses up to 199,000 BTUs of natural gas to deliver a max flow rate of 10 GPM. It utilizes non-condensing technology to achieve an Energy Factor of 0.82. This model meets Ultra-Low NOx emission requirements, and comes with a 15-year limited warranty. A. O. Smith's ProLine water heaters are residential products built to commercial-grade standards and are only available for purchase through professional wholesalers and contractors.
Features:
Specs
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| Product Type: | Tankless Heater |
|---|---|
| Fuel Type: | Natural Gas Propane |
| Inlet Gas Pressure: | 4.0-10.5"W.C |
| Gas Connection: | 3/4" |
| Water Connection: | 3/4" |
| Gas Input: | 15000 to 190000 BTU/h |
| Voltage: | 120v |
| Energy Factor: | 0.82 |
| Installation Type: | Outdoor Only |
| Max Flow (GPM): | 10 |
| Depth (Inches): | 9-1/2" |
| Height (Inches): | 20.5" |
| Width (Inches): | 13-3/4" |
| Weight (lbs): | 40 lbs |
| BTU (Max): | 190000 |
| BTU (Min): | 15000 |
| Vent Type: | Outdoor (No Venting) |
| Type: | Non-Condensing |
| Application: | Residential |
| Includes: | Gas Conversion Kit |
| Flow Rate at 40F Temp Rise (GPM): | 8.3 |
| Flow Rate at 50F Temp Rise (GPM): | 6.9 |
| Flow Rate at 60F Temp Rise (GPM): | 5.5 |
| Flow Rate at 70F Temp Rise (GPM): | 4.8 |
Questions?
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2 Replacement Parts
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