G2 Gas Fitter Practice Exam

What is the design configuration of a high boy forced air gas furnace?

1. Supply air exiting at the bottom and return air entering at the top

2. Supply air exiting at the top and return air entering at the bottom

3. Balanced supply and return air through the sides

4. Supply air escaping through vents on the front and return air from the sides

The correct answer is: Supply air exiting at the top and return air entering at the bottom

A high boy forced air gas furnace is characterized by its design where the supply air exits at the top and the return air enters at the bottom. This configuration allows for efficient heat distribution throughout the space, as the heated air rises naturally due to its lower density compared to cooler air. This design takes advantage of the principles of convection, where warm air rises and cooler air descends, creating a natural circulation pattern in the room. The location of the return air at the bottom helps to pull in the cooler air to the furnace for reheating, thus maintaining an even temperature distribution within the area being heated. The other configurations described do not align with the typical operating principles of a high boy forced air gas furnace. For instance, a system with supply air exiting at the bottom would result in inefficient heat delivery and potential discomfort in the heated space. Similarly, a balanced design with supply and return air through the sides would not utilize the natural convection currents effectively, leading to uneven heating.