When should chemicals be added to the water during boiler drying?

The optimal time to add chemicals during the boiler drying process is when the drum level is one-third of the gauge glass. This approach ensures that the chemicals can adequately mix with the water and affect the entire volume within the boiler. By adding them at this stage, it allows sufficient time for the chemicals to react and perform their intended function, leading to effective treatment.

If chemicals are added after the water is filled to the top, it can lead to uneven distribution, as the water may be less turbulent and the chemicals might not mix well. Adding them before any water is introduced could mean that the chemicals do not serve their purpose since they would not come in contact with the water until it is actively circulating. Moreover, waiting until the boiler has cooled completely is not advisable since effective treatment relies on water circulation and the presence of water for chemical interaction.