Final answer:
Wet-base boilers have a combustion area submerged in water, leading to direct heating, while dry-base boilers heat water through flue passages with combustion occurring in a separate chamber.
Step-by-step explanation:
The difference between a wet-base and a dry-base boiler lies in their design and the way in which the heat is exchanged between the combustion gases and the boiler water. In a wet-base boiler, the burner is submerged in a pool of water that forms the lowest part of the firebox. The combustion takes place directly above this pool of water, which means the base of the boiler is always wet, hence the name. The water absorbs the heat of the combustion directly, providing efficient heat transfer.Conversely, a dry-base boiler has a firebox that is not submerged in water. Instead, the combustion gases rise up through a series of flue passages to heat the water that is contained in the boiler sections above. Since there is no water at the combustion chamber base, this type is referred to as a dry-base boiler. The design difference may contribute to variations in efficiency, maintenance requirements, and suitability for different applications or installations.