New York Low Pressure Boiler COF Practice

In a boiler system, what can never be made of cast iron?

1. Blow off cocks over 200 psi

2. Control valves

3. High temperature water boiler valve bodies

4. Feedwater piping

The correct answer is: High temperature water boiler valve bodies

In a boiler system, high temperature water boiler valve bodies should never be made of cast iron due to the material's limitations in handling high-temperature applications. Cast iron, while strong and good for certain components, is susceptible to cracking and degradation when subjected to the thermal stresses associated with high temperature and pressure conditions. Therefore, using materials that can withstand these extreme environments, such as stainless steel or brass, is essential for ensuring safety and reliability in a boiler system. The other options involve components that may be made from cast iron, as they do not operate under the same extreme conditions as high temperature water boiler valve bodies. For instance, blow-off cocks and some control valves can be designed with cast iron in mind, provided they are rated appropriately, and feedwater piping can also utilize cast iron depending on the design and operating conditions. Thus, the material choice is crucial for maintaining the integrity and safety of boiler operations.