Arkansas Boiler Operator Practice Exam

If a boiler is not kept clean internally, what is the most likely outcome regarding scales?

1. Scales will form and the boiler may not blister

2. Scales will improve boiler efficiency

3. Scales will block the flow of steam

4. Scales will help prevent corrosion

The correct answer is: Scales will form and the boiler may not blister

When a boiler is not maintained in a clean condition internally, scaling can occur. Scaling refers to the buildup of mineral deposits, which is especially common when hard water is used. As water heats up within the boiler, minerals like calcium and magnesium precipitate out and adhere to the internal surfaces, resulting in a layer of scale. The outcome of scale formation in a boiler generally leads to several negative consequences, such as reduced heat transfer efficiency and potential overheating of the boiler surfaces. Accumulation of scale usually does not lead to blistering, which often results from overheating due to poor heat transfer. While scale is detrimental and can impede the boiler's performance, the statement correctly identifies that scales can indeed form without directly causing blistering in every scenario. While scaling can block the flow of steam, improve efficiency, or prevent corrosion in some contexts, those statements are generally misleading regarding the typical operation of a boiler. In most cases, the accumulation of scale will hinder rather than help boiler performance.