TK-540X3-NEH AO Smith 199,000 BTU Natural Gas Outdoor Condensing Ultra-Low NOx w/X3 Technology Tankless Water Heater - ENERGY STAR® qualified
- X3® Scale Prevention Technology
- 15-year limited Heat Exchanger Warranty, 5-year parts warranty, 1-year labor warranty for Residential applications
- Commercia-Grade Copper Heat Exchanger
- Approved to work with an external recirculation pump and cross-over valve
- Complies with Ultra-Low NOx regulations of less than 14 ng/J (<20ppm)
- Condensing Natural Gas Outdoor model
- Safety features include freeze, overheat, surge protection, and troubleshooting diagnostic codes