Technical Standards and Safety Authority (TSSA) G3 Practice Exam

Which of the following does not have an air circulating blower?

1. Make up air unit

2. Unit heater

3. Rooftop package unit

4. Gravity warm air system

The correct answer is: Gravity warm air system

The gravity warm air system is designed to operate using the natural convection of air rather than relying on mechanical means to circulate air. This system takes advantage of the basic principle that warm air rises and cool air descends, allowing for a passive movement of warm air throughout the space. As a result, it does not require an air circulating blower to function effectively. In contrast, the other systems mentioned—make up air units, unit heaters, and rooftop package units—utilize air movers or fans to actively circulate heated or conditioned air to provide adequate comfort in building spaces. These systems rely on blowers to distribute air efficiently, ensuring that heated or cooled air reaches various areas of a structure. Understanding the function and components of different heating systems helps clarify why gravity warm air systems do not include air circulating blowers, highlighting the difference in operational mechanics among these types of equipment.