Oil fired water heaters use an oil burner and a combustion chamber (similar to an oil-fired furnace), which is located below the tank, as the heat source to heat the water. When the thermostat (at the bottom of the tank) senses that the water temperature has fallen below the preset limit, the oil burner will ignite. A jet-like flame is created in the combustion chamber to heat the bottom of the tank. In addition, the hot exhaust gases from the combustion chamber are vented either through a hollow core at the center of the tank (like a gas-fired system) or around the tank to help heat the water. The exhaust is then passed into the vent connector and directed to a chimney flue.