What airflow percentage should be maintained for a boiler during a prolonged shutdown?

Maintaining airflow at 25% of full load during a prolonged shutdown is important for several reasons. First, it helps to ensure that there is sufficient air circulation within the boiler system to prevent the accumulation of combustible gases and to reduce the chance of condensation. This airflow level is low enough to minimize energy consumption while still providing adequate ventilation.

During a shutdown, particularly a prolonged one, components of the boiler may be susceptible to corrosion or other forms of degradation if they are not properly ventilated. Keeping the airflow at this percentage allows for a balance between minimizing potential issues related to moisture buildup and ensuring that the system remains safe and in good working condition.

In contrast, higher percentages of airflow may lead to unnecessary energy usage and costs without providing additional benefits during a shutdown. Maintaining airflow below 25% is typically seen as insufficient for effective ventilation, making 25% the optimal choice for this scenario.