A boiler is also called a steam generator, which is designed to burn fuel. The team space of boiler consists of the portion of the boiler not filled with water. Since the heat in a boiler system radiates out from the radiator into the air that already exists, no new air is entering the space.
Steam boiler functions and terms: Furnace: It is the chamber formed by the area above the grate and below the boiler shell, in which combustion takes place. Water space and steam space: The volume of the shell that is occupied by the water is termed water space while shell volume is less water and tubes called steam space.