NATE Gas Heating Practice Exam

What will energize the indoor fan motor on a thermostat subbase?

1. Gas valve

2. Indoor fan motor

3. Outdoor fan motor

4. Compressor

The correct answer is: Indoor fan motor

The indoor fan motor is energized by the thermostat subbase when there is a demand for heating or cooling within the system. When the theromstat calls for heating, it closes a circuit, which allows a voltage—usually 24 volts—to flow to the indoor fan motor. This process initiates the fan's operation, helping circulate air throughout the living space. In a typical HVAC setup, the fan's function is critical for effective heat distribution, as it helps to disperse warm air emitted from the furnace or heat exchanger. By energizing the indoor fan motor upon a heating or cooling demand, the system ensures efficient temperature regulation and comfort within a building. This is why the answer highlighting the indoor fan motor is correct, as it directly relates to its role in the fan operation in response to thermostat settings. The other choices, while integral components of a heating and cooling system, do not energize the indoor fan motor directly or serve the same function. The gas valve primarily controls the flow of gas to the furnace, the outdoor fan motor is associated with the condenser in air conditioning systems, and the compressor is responsible for circulating refrigerant in cooling systems. Their functions, while vital to the overall HVAC operation, do not impact the operation of the