What does the term "overheating" in a boiler typically indicate?

The term "overheating" in a boiler typically indicates a condition where the water temperature exceeds safe limits, thereby posing a risk of damage to the boiler itself. When overheating occurs, it can potentially lead to several hazardous situations, including boiler failure or pressure vessel damage.

When the temperature of the water rises beyond its safe operating limits, it can result in the production of superheated steam, which can lead to excessive pressure within the boiler. If not controlled, this situation can compromise the structural integrity of the boiler and lead to catastrophic failures like explosions or leaks. Therefore, monitoring and maintaining the correct temperature is crucial to safe boiler operation.

In contrast, the other options do not accurately define overheating. For example, a steady increase in fuel consumption doesn't necessarily correlate to overheating; it might indicate increased demand or inefficiencies without implying direct thermal risk. Operational temperature ranges are considered safe and normal, while an increase in steam pressure under controlled circumstances can be part of normal operations, not indicative of overheating unless safety limits are exceeded.