Define the term “draft” in the context of combustion systems.

In the context of combustion systems, "draft" refers to the flow of air or gases through the flue system. This flow is essential for efficient combustion as it helps to draw air into the combustion zone and ensures that the combustion gases are properly vented outside. A balanced draft system maintains the necessary airflow to support optimal burning conditions, and it also contributes to the overall efficiency of the heating system.

Proper draft is crucial because insufficient draft can lead to incomplete combustion, which results in lower energy output and higher emissions. Conversely, excessive draft can cause too much air to enter the system, which may cool the combustion process and lead to inefficient burning. Thus, maintaining the right draft is vital to ensure safety and effectiveness in combustion systems.