What is a potential consequence of a low water level in a boiler?

A low water level in a boiler can lead to overheating of tubes and steam surging, which are serious concerns in boiler operation. When the water level is insufficient, there is not enough water to absorb the heat generated by the combustion of fuel. This can cause the metal tubes that contain the water to become excessively hot, leading to a condition known as overheating. Overheated tubes can weaken or even rupture, posing severe safety risks and potentially causing catastrophic failures.

Additionally, with insufficient water, steam can form rapidly and unevenly, leading to steam surging. This can disrupt the normal flow of steam within the system and can result in pressure fluctuations. Such scenarios can impact the overall operational stability of the boiler, potentially leading to further mechanical issues and increased maintenance costs.

In contrast, the other options suggest outcomes that would not logically follow from a low water level. Decreased fuel consumption, reduced emissions, and improved efficiency are generally associated with well-operated systems that maintain appropriate water levels. Inadequate water levels would typically lead to increased fuel use and harmful operational conditions rather than improvements in efficiency or environmental performance.