What is typically used to treat water hardness in a boiler system?

The correct choice for treating water hardness in a boiler system is phosphate. Phosphates are added to boiler water because they effectively react with calcium and magnesium ions, which are the primary contributors to water hardness. This reaction forms insoluble compounds that can be removed from the boiler system, preventing the scale buildup that can lead to reduced efficiency and damage to the boiler.

Phosphates also help to maintain a stable pH level in the water, which is beneficial for protecting the boiler materials from corrosion and further ensuring the overall efficiency of the system. By employing phosphates, operators can manage water quality effectively, thus extending the lifespan of the equipment and improving operational performance.

In contrast, acetic acid would lower pH and could lead to corrosion, sodium carbonate is more commonly used for softening water rather than direct treatment of hardness in boiler systems, and hydrochloric acid is primarily utilized for cleaning and not for treating boiler feedwater. The specific role of phosphates underscores their importance in maintaining water quality suitable for efficient boiler operation.