What condition may lead to a decrease in boiler efficiency?

Heating surface fouling is a condition where the material that generates heat or transfers it to water becomes coated with deposits, which can include rust, scale, or other residues. This fouling acts as an insulating layer that reduces the effective area available for heat transfer. Consequently, the heat generated by the combustion process is not efficiently transferred to the water in the boiler, leading to lower overall efficiency.

When the heating surfaces are clean, they can transfer heat more effectively, resulting in improved boiler performance. However, when fouling occurs, the boiler must work harder to achieve the same output, leading to increased fuel consumption and ultimately reducing efficiency. Therefore, managing the cleanliness of heating surfaces is crucial in maintaining optimal boiler performance and efficiency.