Reliance 6.6 gal 160000 BTU Natural Gas Tankless Water Heater

"15 year warranty heat exchanger, 5 year warranty parts, 97% UED recovery efficiency, .94 Uniform Energy Factor (UEF), condensing indoor model, meets California Ultra Low NOx emission rules, requires 3/4"" gas line,150 psi Pressure only relief valve not included-purchased separately, recommend ordering isolation valve kit that includes the 150 psi pressure only valve, and two service valves, which makes required periodic maintenance easier, order Ace 4699856 separately, requires 120 volt power supply, warranty will not cover damage caused by water quality, Dimensions and specifications subject to change without notice in accordance with our policy of continuous product improvement"