The performance parameters of boiler efficiency and evaporation ratio diminish with the age due to poor combustion, heat transfer surface fouling and poor operation and maintenance. For a new boiler also, deteriorating fuel quality and water quality can result in poor boiler performance.

Surface fouling:

• The vaporization of volatile inorganic elements in coal during combustion is the most common cause of fouling.
• When heat is absorbed and temperatures drop in the boiler's convection area, the compounds formed by these elements condense on the ash particles and heating surface, forming a glue that starts deposition.
• Surface fouling can negatively affect power plant reliability and efficiency.

Poor combustion:

• Incomplete or poor combustion will occur if there is insufficient air.
• If an insufficient amount of air is supplied to the burner, unburned fuel, soot, smoke, and carbon monoxide are exhausted from the boiler.
• The results are surface fouling, pollution, lower combustion efficiency, flame instability, and the risk of explosion or backfire.

Boiler mounting:

• Boiler mountings are the components that are usually mounted on the surface of the boiler to ensure its safety while in use.
• These are the boiler's essential components, without which the boiler cannot function.

Poor water quality:

• Impurities and gases in low-quality boiler feed water can harm the entire system.
• This will result in a decrease in efficiency and, worse yet, boiler or system leaks.