What is a potential consequence of scale sloughing off when a boiler is restarted?

When a boiler is restarted, scale that has formed on the heat transfer surfaces may break loose and slough off. This process can lead to the accumulation of scale in various parts of the boiler system, particularly in pipes and fittings. When scale accumulates, it can create obstructions that restrict the flow of water and steam within the system. This reduced flow can cause several issues, including increased pressure and temperature, as well as inefficient heat transfer, which ultimately jeopardizes the safe and efficient operation of the boiler.

The incorrect options, while relevant to boiler operation, don't describe the direct consequence of scale sloughing off. For instance, an increased flow rate typically relates to well-maintained systems that are free from obstructions, while improved thermal efficiency and enhanced safety measures typically occur in systems that are clean and appropriately maintained, rather than those experiencing scale buildup. Thus, the potential consequence of scale sloughing off is primarily the accumulation of scale that restricts flow, which can lead to various operational issues in the boiler.