Which components typically provide input signals to a high-efficiency furnace control board?

In a high-efficiency furnace, the control board is a crucial component that manages the operation of the entire heating system. It receives input signals from various components to function effectively.

The thermostat is essential as it senses the temperature in the living space and communicates the heating demand to the control board. When the temperature drops below the set point, the thermostat signals the control board to initiate the heating process.

The flame sensor circuit is another vital input. This sensor detects whether the flame is present after the gas valve opens. If the flame is not detected, it signals the control board to shut off the gas valve to prevent the buildup of unburned gas, ensuring safety and efficiency.

Limit controls are also important. These devices monitor the temperature within the furnace and ensure that it does not exceed safe operating levels. If the limit control detects that the furnace is overheating, it sends a signal to the control board to deactivate the gas valve and stop the heating process.

Together, the thermostat, flame sensor circuit, and limit control provide the necessary feedback for the furnace to operate safely and efficiently, making this option the best answer. This integrated feedback system enables the furnace to maintain optimal performance and avoid potential hazards.