What is the likely cause when boiler flues require frequent cleaning?

• A. Excessive humidity in the flue
• B. Inadequate combustion of fuel
• C. Corrosion in the flue pipes
• D. Insufficient fuel supply

Answer: (B)

Frequent cleaning of boiler flues is typically indicative of inadequate combustion of fuel. When combustion is incomplete, it results in a buildup of residues such as soot, which accumulates in the flue pipes. This can happen due to a number of factors, including improper air-to-fuel ratios, poor maintenance of the burner, or the use of low-quality fuel. This residue not only requires regular cleaning but can also impact the efficiency of the boiler, leading to further operational issues if not addressed.

In contrast, excessive humidity in the flue can lead to condensation, which may cause different issues but does not directly result in the same level of frequent cleaning needs as a buildup from incomplete combustion. Corrosion in flue pipes, while problematic, typically is more of a long-term concern rather than a reason for frequent cleaning. Additionally, insufficient fuel supply will lead to a range of operating problems but won't necessarily cause increased residue that requires cleaning.