What is the primary benefit of flue gas passages in cast-iron sectional boilers?

Flue gas passages in cast-iron sectional boilers serve to enhance heat transfer efficiency. As flue gases—resulting from combustion—pass through these specially designed channels, they come into direct contact with the boiler's heat-exchanging surfaces. This design maximizes the surface area available for heat transfer, allowing more heat from the combustion gases to be absorbed by the water in the boiler.

Increased heat transfer means that the boiler can operate more efficiently, achieving higher temperatures without requiring more fuel. This not only optimizes energy usage but can also lead to reduced operational costs over time. Overall, the design of the flue gas passages is integral to the boiler’s ability to generate steam or hot water effectively, thus highlighting their primary benefit.