Excess air in a boiler system can lead to which of the following issues?

Excess air in a boiler system refers to the condition where more air is supplied for combustion than is theoretically needed for complete fuel combustion. This surplus air can significantly affect boiler operation due to various factors.

When excess air is introduced, it carries away heat that could otherwise be used for heating water or steam generation. The additional air results in the dilution of flue gases, leading to higher stack temperatures. This means that some of the heat produced during combustion is wasted, resulting in heat loss. Consequently, the overall efficiency of the boiler system diminishes, as more energy is required to achieve the same output.

Increased fuel consumption occurs as the boiler system strives to produce more energy to compensate for the heat loss. However, it is important to note that increased efficiency is directly contradictory to the effects of excess air. Excess air does not enhance combustion efficiency; rather, it detracts from it, leading to lower efficiency and increased operational costs.

Cooler flame temperatures can also be a consequence of excess air, as the extra oxygen can cause the flame to burn less intensely. However, the most direct and significant issue associated with excess air in a boiler system is indeed heat loss and low efficiency.