What does smoke or cloudy exhaust from the stack indicate?

Smoke or cloudy exhaust from the stack is a clear indication of incomplete combustion occurring within the boiler. Incomplete combustion happens when there is not enough oxygen present to convert all the fuel into carbon dioxide and water vapor. Instead, some of the carbon in the fuel is released as soot and other particulates, leading to the visible smoke or haze in the exhaust.

This phenomenon is critical to understand because it not only affects the efficiency of the boiler operation but also indicates potential safety hazards, such as the buildup of unburned fuel, which can lead to dangerous conditions like explosions or increased emissions of harmful pollutants. Recognizing and addressing the causes of incomplete combustion can lead to more efficient fuel usage, reduced emissions, and safer boiler operations.