A disadvantage of a cast iron boiler is:

A cast iron boiler can be prone to leaks between its sections due to the way it is constructed. Cast iron boilers are typically made up of multiple sections that are bolted together. Over time, thermal expansion and contraction can affect the integrity of the joints between these sections, especially if the boiler experiences frequent temperature fluctuations. Additionally, wear and tear or improper maintenance can exacerbate the potential for leaks.

Understanding this characteristic is essential because leaks can lead to water loss, reduced efficiency, and the risk of more significant operational issues. By knowing the vulnerability of sectioned joints in cast iron construction, operators can prioritize regular inspections and maintenance to address any potential leaks before they become problematic.

In contrast, while cast iron can exhibit susceptibility to corrosion due to its iron content, this is not a unique disadvantage compared to other materials used in boiler construction. The assembly process for cast iron boilers can be complex, but many technicians are familiar with it, making it less of a significant disadvantage given the deep-rooted industry practices. The cost of cast iron boilers can vary significantly based on design and quality; hence it may not always be classified as "extremely high" compared to other boiler types, which can also be costly depending on various factors.