Which of the following is NOT considered a heat loss in a boiler?

Heat gained from the surroundings is not considered a heat loss in a boiler. Heat loss refers to energy that escapes from the system, reducing the efficiency and effectiveness of the boiler in generating steam or hot water. When considering how a boiler operates, it's essential to understand that it generates heat primarily from the combustion of fuel.

Moisture in the air, dry flue gases, and unburned carbon in the ash all represent different forms of energy loss. Moisture in the air can absorb heat, taking energy away from the combustion process. Heat carried away in dry flue gases indicates that some of the heat produced is escaping along with exhaust gases, which can diminish the boiler's efficiency. Unburned carbon in the ash signifies that not all of the fuel is being utilized effectively, resulting in a loss of potential heat energy that could have been converted into useful work. In contrast, heat gained from the surroundings implies that energy is being absorbed rather than lost, thus benefiting the boiler operation rather than detracting from it.