Which scenario likely indicates that the induced draft fan is malfunctioning?

When considering the scenario in which the induced draft fan is malfunctioning, the absence of voltage to the fan motor is a clear indication of a problem. The induced draft fan plays a critical role in ensuring that combustion gases are vented properly from the furnace. This function helps maintain a safe and efficient combustion process.

If there is no voltage reaching the fan motor, it means that the fan cannot operate, thereby preventing the necessary airflow that helps to remove gases from the combustion chamber. This lack of operation can lead to dangerous conditions, such as the buildup of harmful gases and reduced efficiency of the heating system.

Understanding the implications of voltage loss helps HVAC technicians diagnose issues effectively. The induced draft fan’s operation is essential for proper exhaust and combustion, and loss of voltage is a definitive sign that a malfunction is present. This knowledge is crucial for maintaining system safety and operational efficiency.