The Eccotemp FVI12 Indoor Natural Gas Tankless Water Heater delivers efficient performance with a flow rate of 4.0 GPM and a temperature rise of 38 degrees. Rated at 74,500 BTU per hour, this model can comfortably meet your hot-water requirements. Featuring manual temperature controls, the temperature can be easily set and adjusted via the front control panel, ensuring optimal heat regulation directly from the water heater and not from your sink or shower. This model is pressure activated and not recommended for well water systems, submerged pumps, or bilge pumps. In locations without municipal water supply, a 55 PSI diaphragm pump is recommended to ensure proper functionality. We recommend the Eccotemp FVI12-NG for smaller single family homes, apartments, condos, or cabins. Using 1-2 hot water applications simultaneously is a breeze with the Eccotemp FVI12-NG. With our upgraded PCB (Product Control Board) performance and an all new gas modulating valve, consumers can experience best in class temperature performance with a price anyone can afford. The compact, wall mounted Eccotemp FVI12-NG has a 110/120V UL listed power cord that powers the internal Exhaust Fan, Digital Display and PCB. The Eccotemp FVI12 has been tested for use at elevations up to 2000 ft. Installation and use of the Eccotemp FVI12 above 2000 ft. may affect overall product efficiency and performance. IMPORTANT NOTE: Cannot be used for HYDRONIC SYSTEMS, RECIRCULATING, or FLOOR HEATING.