What should be opened by the inspector when inspecting heating systems?

When inspecting heating systems, the inspector should focus on accessing components that can be readily opened without requiring excessive effort or causing damage. Access panels that are readily openable allow the inspector to examine critical parts of the heating system to ensure they are functioning correctly and safely. These panels provide access to areas where components like the heat exchanger, burners, and fan assemblies might be located, facilitating a thorough inspection.

The emphasis is on the term "readily openable," which implies that these access panels can be opened without specialized tools, forcing, or disassembly that could compromise the structure of the system. Faulty components or inadequate system maintenance can often be identified when these panels are accessible, enabling the inspector to provide an accurate assessment of the heating system’s condition.

In contrast, other options may not provide the same level of accessibility or insightful information about the system's integrity. For example, wall panels or air duct covers might not lead to the main components of the heating system or might involve more complexity to access, potentially not being allowed under standard inspection practices. Furnace doors may also be a consideration, but they often fall under specific handling or operational guidelines that may be outside the scope of a general inspection unless they are explicitly designed for such access.