What are the three types of drafts found in boiler systems?

The correct answer, which identifies the three types of drafts in boiler systems, is natural, forced, and induced.

Natural draft relies on the natural buoyancy of hot gases; as the air heats up, it rises and creates a difference in pressure that draws in fresh air for combustion. This method is generally used in simpler or smaller systems where airflow can be managed simply through temperature variations.

Forced draft involves mechanical fans or blowers to push air into the combustion chamber. This type provides a more controllable and consistent airflow, which can be adjusted according to the system's operational needs. It is commonly used in larger or more complex boiler systems where increased efficiency and power are required.

Induced draft systems use a fan to remove flue gases from the heat exchanger and push them outside, creating negative pressure in the combustion chamber. This type of draft ensures that the combustion process is efficient by effectively managing the flow of exhaust gases.

Understanding these draft types is crucial for maintaining boiler efficiency and safety, as they directly impact combustion performance and the overall system operation.