For this atmospheric vent propane gas heater, air is drawn from inside the home and the exhaust is vented into a chimney or through the roof. It features the Flame Guard® Safety System, which reduces the risk of accidental fires involving flammable vapours from products such as gasoline, paint thinner or solvents. This 33 gallon 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 lets you 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 visual confirmation that the pilot is on, 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.