Technical Standards and Safety Authority (TSSA) G3 Practice Exam

What does the term "natural draft" refer to in burners?

1. Utilizes forced air for combustion

2. Operates without an external power source

3. Requires ongoing manual intervention

4. Employs electrical ignition systems

The correct answer is: Operates without an external power source

The term "natural draft" in burners refers to a system that operates without an external power source. This type of system relies on the natural buoyancy of hot gases to create a draft that draws air into the combustion chamber and exhausts gases through a flue or chimney. As the gases rise, they create a negative pressure that pulls fresh air into the burner, allowing for combustion to occur primarily through natural airflow rather than mechanical means. In contrast, systems that utilize forced air for combustion rely on fans or blowers to introduce air into the burner, making them dependent on an external power source. Similarly, ongoing manual intervention is not a characteristic of natural draft burners, as they are designed to operate autonomously once ignited. Electrical ignition systems, on the other hand, also require an external energy source for their operation, which does not align with the concept of natural draft. Thus, the key aspect of natural draft is its reliance on passive forces, making it efficient in certain systems where external power is not feasible or intended.