Reliance 6.6 gal 160,000 BTU Propane Tankless Water Heater

15 year warranty heat exchanger, 5 year warranty parts, 97% UED recovery efficiency, .94 Uniform Energy Factor (UEF), condensing outdoor 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 4699856 separately, up to 6,000 feet altitude, requires 120 volt power supply, Remote controller is NOT waterproof, do not extend remote control wiring more than 400 feet, 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