G2 Gas Fitter Practice Exam

How does a residential central forced air gas furnace heating system function?

1. Cycles air through a heat pump

2. Draws conditioned air and circulates it

3. Returns cold air through the ducts

4. Utilizes radiant heating panels

The correct answer is: Draws conditioned air and circulates it

In a residential central forced air gas furnace heating system, the correct function involves drawing conditioned air and circulating it throughout the living spaces of the home. The system works by first pulling in cooler air from the rooms via returns. This air then passes through a filter where dust and particulates are removed. Once filtered, the air is directed to the furnace, where it is heated by burning gas. The heated air is then forced through the ductwork by a blower fan, distributing warm air into various rooms through vents. This process ensures a consistent and comfortable temperature in the home, effectively utilizing the principles of convection. While other options mention heating processes, they do not accurately describe the specific operation of a forced air gas furnace. For instance, option A mentions a heat pump, which operates differently by using refrigerants and is not reliant on combustion processes. Option C focuses on returning cold air, which is part of the overall cycle but does not describe the heating function itself. Option D refers to radiant heating panels, which operate on a completely different concept involving the direct transfer of heat through radiation instead of forced air circulation. Thus, option B captures the essential functioning of a central forced air gas heating system accurately.