Which term describes air that cools equipment?

• A. Processed air
• B. Primary air
• C. Secondary air
• D. Outside air

Answer: (A)

Air streams around gas-fired equipment are defined by their purpose. Primary and secondary air are specifically the portions of air that support the combustion process inside the burner, with primary air mixing with the gas and secondary air aiding complete combustion. Outside air refers to fresh air brought in from outdoors, typically for ventilation or makeup air, not for cooling components. Processed air, on the other hand, describes air that has been conditioned or treated for use in the system, such as for cooling equipment. That conditioning makes it suitable to remove heat from components without participating in the flame chemistry. So air that cools the equipment is best described as processed air, since its role is cooling rather than combustion or ventilation.