Which of the following is NOT a benefit of using sodium sulfite in boilers?

Using sodium sulfite in boilers is primarily aimed at preventing oxidation and controlling the chemical environment within the boiler system. One of the key benefits is its ability to reduce oxygen levels in water, which helps to prevent corrosion of boiler components. This oxidation prevention is critical for maintaining the integrity and longevity of the boiler.

Another benefit is related to the control of alkalinity within the boiler water. Proper alkalinity levels are essential for minimizing scaling and other issues that can arise from imbalanced pH levels. Sodium sulfite can help to manage this aspect effectively.

Additionally, sodium sulfite can impact the foaming tendencies of boiler water. By mitigating foam formation, it helps ensure better heat transfer and more efficient operation, which can be critical in maintaining performance.

However, improved thermal efficiency is not a direct benefit attributed to sodium sulfite. While maintaining a clean and properly chemically treated boiler can contribute to thermal efficiency, the role of sodium sulfite itself does not inherently lead to improved thermal efficiency. Instead, the benefits of sodium sulfite focus more on protection against corrosion, control of water chemistry, and reduction of foaming rather than directly enhancing the efficiency of heat transfer within the boiler system.