What is the term for the air that is mixed with gas for combustion?

The term that describes the air mixed with gas for combustion is primary air. Primary air is essential in the combustion process, as it provides the oxygen needed to facilitate the burning of the fuel. It typically enters the combustion chamber through strategically located openings, ensuring that efficient and complete combustion occurs. This is crucial for achieving optimal heating performance and reducing emissions.

Understanding the role of primary air is fundamental in HVAC applications, especially when dealing with gas-fired equipment. Proper air-to-fuel ratios are key to ensuring efficiency and safety. By controlling the amount of primary air, technicians can influence combustion efficiency and the performance of heating appliances.

In contrast, secondary air involves air that is introduced after the initial combustion has begun, typically to help complete the combustion process. Excess air refers to the additional air supplied beyond what is needed for complete combustion, which can lead to reduced efficiency and increased emissions if not managed properly. Combustion air is a broader term that can refer to both primary and secondary air but does not specifically denote the air mixed with the gas before ignition.