What is a primary disadvantage of a cast iron boiler?

The primary disadvantage of a cast iron boiler is indeed its pressure limitations. Cast iron is a robust material known for its durability and strength; however, it has a relatively low tensile strength compared to other metals such as steel. This characteristic restricts the maximum allowable working pressure of cast iron boilers, making them unsuitable for high-pressure applications. They are typically limited to lower pressure settings, which can be a significant disadvantage in industries or applications where higher pressures are required for efficiency or operational needs.

Furthermore, it's important to recognize that while operational costs, weight, and thermal conductivity are relevant factors, they do not define the primary disadvantages in the same way. For instance, cast iron boilers tend to have higher initial costs due to their construction, and they are indeed heavier, making installation more challenging. However, these factors do not typically impact the overall operational effectiveness and safety as significantly as the pressure limitations do.