What is the purpose of adding baking soda or soda ash when deliming boilers?

The addition of baking soda or soda ash when deliming boilers serves the essential purpose of neutralizing acids and preventing damage to the boiler system. When de-scaling a boiler, acidic solutions are often used to dissolve mineral build-up and limescale. However, after the cleaning process, residual acidity can remain, which may lead to corrosion and damage to metal components if not properly managed. By introducing baking soda or soda ash, the acidity is neutralized, thus protecting the boiler's integrity and prolonging its lifespan. This neutralization process is crucial to ensure that the system operates safely and effectively, avoiding costly repairs and maintenance issues in the future.

The other choices, while related to boiler maintenance and water treatment, do not directly capture the primary function of adding these substances during the deliming process.