What can result from a failure of an air vent in a steam heating system?

A failure of an air vent in a steam heating system can indeed lead to waterlogging of the system. In a properly functioning steam heating system, air vents serve the crucial role of releasing trapped air from the system. When air accumulates in the system and is not effectively vented, it can create air pockets that block steam from circulating properly.

When steam can't fill the pipes and radiators effectively due to trapped air, the steam condenses into water, leading to waterlogging. This occurs when water accumulates in the low points of the piping or radiators because the steam is unable to replace it due to the obstruction caused by the trapped air. Waterlogging can significantly diminish the heating efficiency of the system, as it hampers the intended flow of steam and can potentially lead to operational issues or damage over time.

In contrast, excessive steam pressure and improved heating distribution are typically outcomes associated with proper function, while increased energy efficiency is not a result of air vent failure, as ineffective air elimination leads to wasted energy and reduced system efficiency.