Final answer:
To check a hydronic system in a basement, inspect the boiler or furnace, piping, radiators, and all components for proper functioning and potential leaks. Radon levels in the basement should also be considered as a health concern.
Step-by-step explanation:
The question pertains to inspecting a hydronic heating system, which is a type of heating system that uses water to transfer heat. When entering a basement to inspect a hydronic system, one would typically look for the boiler or furnace, piping, radiators, and associated components such as the expansion tank and circulation pumps. A comprehensive check would involve examining these components for leaks, ensuring proper pressure and temperatures are maintained, checking the functioning of control systems, and ensuring that there is no blockage or air trapped in the system that could affect its efficiency. Moreover, the homeowner should also be aware of the potential for radon gas accumulation in the basement, as radon can enter through the ground and well water and represents a health risk when inhaled.