🔍 Key Concepts

• Thermal expansion of boiler structure and how the boiler is supported on its foundation • Difference between pressure parts (tubes, headers, nipples) and supporting structure • Purpose of a sliding support/foot compared with water circulation components like headers and nipples

💭 Think About

• Look closely at where arrow "C" is pointing: is it connected to water/steam flow, or is it part of the mechanical support at the base of the boiler? • Ask yourself which options describe items that carry water/steam inside them, and which describe something that would allow the boiler casing or drum to move as it heats and cools. • Consider why a boiler needs to be able to expand and contract lengthwise and what kind of component is installed between the boiler and its foundation to allow that.

✅ Before You Answer

• Verify whether the component at "C" contains tubes or fluid connections; headers and nipples must be part of the pressure circuit. • Check if the object at "C" is at the foundation/base of the boiler rather than in the tube bank area. • Eliminate any choice that obviously belongs in the water circulation system (upper or lower headers, downtake connections) if the illustrated part is clearly just a structural support.