What is the main purpose of an air vent in steam heating systems?

The main purpose of an air vent in steam heating systems is to remove air from the system. When steam heating systems are filled with water and subsequently heated, air that was present can create air pockets or traps, which hinder the efficient flow of steam and can affect the heating performance. Venting allows trapped air to escape, thereby ensuring that the steam can circulate freely throughout the system. This is crucial for maintaining optimal system efficiency and preventing issues like water hammer or uneven heating in radiators, as steam should replace the air to adequately transfer heat. By facilitating the removal of air, the air vent plays a vital role in maintaining the overall functionality and effectiveness of steam heating systems.