What is a potential problem caused by hard water in boilers?

Hard water contains high concentrations of dissolved minerals, primarily calcium and magnesium. When hard water is heated in a boiler, these minerals can precipitate out as scale, forming deposits on the heat exchange surfaces. Scale buildup can greatly reduce the efficiency of heat transfer, causing the boiler to work harder to maintain desired temperatures. This overheating can lead to further issues such as overheating of components, increasing maintenance needs, and potentially leading to operational failures.

In contrast, while high pressure, frequent shutdowns, and corrosion are concerns in boiler operation, they are not directly caused by hard water. Increased pressure in the boiler can occur for various other reasons, such as overfilling or thermal expansion. Frequent shutdowns could be related to various operational issues, not necessarily linked to hard water. Corrosion can result from other factors such as oxygen in the water or improper chemical treatment, rather than from the presence of scale specifically associated with hard water conditions. Thus, scale buildup and fouling is the most pertinent issue caused by hard water in boilers, leading to reduced efficiency and increased maintenance demands.