A condensing boiler

A condensing boiler

• A. Condenses water in the supply line.
• B. Condenses refrigerant.
• C. Condenses moisture from the flue gases.
• D. Condenses air humidity.

Answer: (C)

Condensing boilers recover extra heat by condensing the water vapor in the combustion flue gases. When fuel burns, it produces water vapor along with other exhaust. The boiler cools these flue gases in a special heat exchanger to below the dew point, causing that vapor to condense. The heat released during this condensation is then transferred back into the heating water, boosting efficiency significantly compared with non-condensing designs. This isn’t about condensing water in the supply line, refrigerant in a refrigeration cycle, or condensing humidity from the surrounding air. Those processes belong to other systems (water handling, cooling/refrigeration, or dehumidification), not to how a condensing boiler extracts heat from its exhaust.

Condensing boilers recover extra heat by condensing the water vapor in the combustion flue gases. When fuel burns, it produces water vapor along with other exhaust. The boiler cools these flue gases in a special heat exchanger to below the dew point, causing that vapor to condense. The heat released during this condensation is then transferred back into the heating water, boosting efficiency significantly compared with non-condensing designs.

This isn’t about condensing water in the supply line, refrigerant in a refrigeration cycle, or condensing humidity from the surrounding air. Those processes belong to other systems (water handling, cooling/refrigeration, or dehumidification), not to how a condensing boiler extracts heat from its exhaust.