NATE Gas Heating Practice Exam

What is the primary function of the combustion blower in a furnace?

1. Mix fuel with air for better combustion

2. Push combustion products out of the building

3. Prevent carbon monoxide from entering the heat exchanger

4. Give the larger blower motor a rest

The correct answer is: Mix fuel with air for better combustion

The primary function of the combustion blower in a furnace is to mix fuel with air for better combustion. This process is crucial because effective mixing ensures that the fuel burns efficiently and completely, producing maximum heat output while minimizing emissions and the production of hazardous byproducts. When the combustion blower operates, it draws in ambient air and forces it into the combustion chamber along with the fuel. This combination facilitates a more complete combustion process, which helps to achieve optimal performance and efficiency of the furnace. Proper mixing also keeps flame temperatures stable and helps prevent issues like soot formation or incomplete combustion. The other roles suggested, such as pushing combustion products out of the building, are typically handled by other components of the furnace system, such as the venting or exhaust systems. Additionally, preventing carbon monoxide from entering the heat exchanger is managed by safety mechanisms and not directly by the combustion blower. Lastly, reducing the workload on the larger blower motor is not a primary function of the combustion blower; each component has distinct responsibilities that contribute to the furnace's overall operation.