For this atmospheric vent propane water heater, air is drawn from inside the home and the exhaust is vented into a chimney or through the roof. This heater features Flame Guard Safety System, which reduces the risk of accidental fires involving flammable vapours from products such as gasoline, paint thinner or solvents. This 40 USG/151 L water heater features: a glass-lined tank to provide superior protection against the corrosive effects of hot water; heavy-duty anode rod for additional tank protection; turbulator dip tube, which reduces sediment build up at the bottom of the tank to prolong tank life; piezoelectric ignitor, which allows you to light the pilot without matches; a thermopile system, which provides a robust pilot to withstand environmental conditions such as down drafts; an LED indicator, which gives you visual confirmation the pilot is lit, and provides diagnostics and troubleshooting information; and a thermostat that allows for easy temperature adjustments. Maintenance is simple with an easy-to-access combustion chamber and conveniently located drain valve.