G2 Gas Fitter Practice Exam

What occurs at the heat exchanger in a heating system?

1. Cool air is absorbed

2. Return air is cooled

3. Return air is heated

4. Heat is dissipated

The correct answer is: Return air is heated

At the heat exchanger in a heating system, the primary function is to transfer heat from the heating medium (such as hot water, steam, or air) to the return air that is circulating through the system. As the return air passes over or through the heat exchanger, it absorbs the heat, resulting in an increase in temperature. This warmed air is then circulated throughout the space being heated, effectively raising the ambient temperature to a comfortable level. The effectiveness of the heat exchanger is critical for the overall efficiency of the heating system, allowing for a significant temperature rise in the return air with minimal energy input. Understanding this process is essential for gas fitters and HVAC technicians, as it directly impacts system performance, efficiency, and comfort levels within a building.