Power vented for positive exhaust during main burner operation—the TTW2 hot water tank uses a specially designed assembly that blows exhaust gases directly out of the building, eliminating the need for conventional chimneys or expensive flue systems. Electronic ignition system 3" PVC, ABS & CPVC (76mm) vent—the water heater can be vented horizontally or vertically with 3" (76 mm) PVC, ABS & CPVC for lengths up to 30 feet (9.1 m) with (3) 90° elbows. (45 equivalent feet) (13.7 m). Vitraglas ® lining Side connections Protective magnesium rod Factory installed Hydrojet ® Total Performance System Factory installed dielectric waterway fittings Fully automatic controls—fast acting surface-mount thermostat for automatic temperature control. Built-in energy cut-off switch prevents abnormally high water temperature for extra safety. Combination gas valve/electronic module has built-in gas pressure regulation and electronic circuit controls. Ignition system operates off of 24 volts. Brass drain valve. T&P relief valve opening Flue baffle Six or ten year limited warranty on steel tank Six year limited warranty on part