What is the purpose of baffles in a hot water boiler?

The purpose of baffles in a hot water boiler is primarily to slow down the flow of hot flue gases as they pass through the heat exchanger. By doing so, baffles increase the contact time between the hot gases and the heating surfaces. This enhanced contact improves heat transfer efficiency, allowing the boiler to extract more heat from the flue gases and effectively transfer it to the water being heated. As a result, the overall efficiency of the boiler is improved, which is crucial for optimizing energy use and reducing operating costs.

In contrast, reducing water flow is not a function of baffles; rather, it is achieved through other means, such as pumps or control valves. Cleaning boiler tubes is also separate from the action of baffles, which do not serve a cleaning function but rather a flow management role. Finally, while air and gas premixing is important for combustion processes, this is typically managed through combustion chamber design and controls, not through the use of baffles in the boiler structure.