- Continuous flow rate up to 8.0 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 integrated temperature controls 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 310U Series is great for two bath homes in cold climates. The 310U features a max flow rate of 8.0 gallons per minute providing enough hot water to run three showers at the same time. The design allows for a variety of installation options. Complies with Ultra-Low NOx regulations and meets energy efficiency requirements of ASHRAE 90.1b-1992. The ATO-310U tankless water heater uses up to 190,000 BTU/h of natural gas/liquid propane to deliver an endless supply of hot water for a 2.5 bath home in northern climates and up to a 3.5 bath home in southern climates (one shower head per bath). The ATO-310U has a Uniform Energy Factor of 0.81. With an industry leading 15-year limited warranty, the ATO-310U tankless water heater provides years of hot water through innovation and quality. 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.