What are the two types of gases produced from combustion?

The correct response identifies the two types of gases produced during combustion as flue gases and vent gases. Flue gases are the gases that are expelled through the exhaust system of combustion equipment, such as a furnace, boiler, or generator. These gases typically include carbon dioxide, water vapor, and other combustion byproducts, depending on the fuel type and condition of the combustion process.

Vent gases, on the other hand, refer to the specific gases that are channeled away from the combustion area toward the environment, ensuring that harmful emissions are properly managed and do not re-enter the living space. This distinction is important in understanding how combustion systems are designed to operate safely and efficiently.

Both terms are essential in HVAC applications because they relate to the system's ventilation, air quality management, and efficiency in burning fuel. Knowledge of flue and vent gases assists HVAC professionals in ensuring compliance with safety regulations and optimizing system performance.