What is a potential consequence of failing to monitor the firing rate adequately?

Monitoring the firing rate in a boiler or combustion system is crucial for maintaining safe and efficient operation. When the firing rate is not monitored adequately, it can lead to overheating, as the system may operate beyond its designed thermal limits. This excessive heat can cause various components to degrade or fail, leading to significant damage to the boiler or the associated equipment.

In addition to the direct impact on system integrity, overheating can also pose safety hazards, such as pressure build-up that may result in catastrophic failures. Therefore, proper monitoring ensures that the fuel is burned at optimal rates, maintaining healthy operating temperatures and preventing unnecessary wear and damage to the system.

The other options suggest positive outcomes—such as increased fuel efficiency, reduced maintenance costs, or improved air quality—which result from proper operation and monitoring, rather than the consequences of failing to do so. Thus, the focus on overheating and system damage directly aligns with the risks of neglecting to monitor the firing rate.