What does the term "minimum draft" mean in relation to a boiler?

The term "minimum draft" refers to the lowest combustion air pressure required for safe operation in a boiler system. In the context of boiler operation, draft is a critical factor because it determines how well the combustion gases are removed from the combustion chamber. Sufficient draft ensures that fresh air can enter for the combustion process while also allowing for the proper exit of exhaust gases. If the draft is too low, it can create unsafe operating conditions, such as a buildup of flue gases, which can potentially lead to hazardous situations.

Understanding the importance of maintaining the minimum draft level is crucial for efficient combustion, effective heat transfer, and the overall safety of the boiler system. An inadequate draft can hinder performance and may result in increased emissions or even boiler shutdown. Therefore, maintaining the appropriate draft is essential for both operational efficiency and safety.