The ProLine® XE water heaters have been engineered to maximize efficiency and deliver a greater uniform energy factor (UEF). ENERGY STAR® qualified 6-year limited Tank warranty, 6-year parts warranty for Residential applications Newly designed LimeFighter® dip tube optimizes inlet water pressure to minimize cold water regions within the tank. The self-cleaning action also reduces sediment accumulation on the bottom of the tank. Hot-surface ignitor is more robust and reliable than standing pilot, and reduces energy consumption Built-in heat traps on the water inlet and outlet reduce the amount of heat lost through piping 2-inch, thick, “Environmentally-Friendly” foam insulation reduces theamount of heat loss and contributes to overall energy efficiency Versatile Power Vent Design All models feature an exclusive 3-position rotatable blower outlet which adds flexibility Combined horizontal and vertical vent runs up to 180 equivalent feet with 4”diameter venting (ABS, PVC, CPVC and polypropylene) All models are equipped with a protected sensor that detects the presence of flammable vapors and automatically disables the burner to prevent ignition Air intake snorkel elevates the inlet location of combustion air to prevent flammable vapors from entering the sealed combustion chamber Reduced NOx emissions comply with air quality management district regulations State-of-the-art electronic gas control provides more precise temperature control LED control light displays operation status and diagnostics information Factory-installed T&P and a durable, tamper-resistant brass drain valve are positioned for service accessibility