What is the function of the gas valve in a gas-burning furnace?

The function of the gas valve in a gas-burning furnace is primarily to control the flow of gas to the burner based on the operational demands of the system. When the thermostat calls for heat, the gas valve opens and allows gas to flow to the burner assembly. This regulation ensures that the right amount of gas is supplied to create the appropriate flame needed for heating. It plays a crucial role in the safety and efficiency of the furnace operation, helping to prevent gas leaks and ensuring that combustion occurs at the correct levels for effective heating.

While the other options mention important functions within a gas furnace system, they do not accurately describe the core responsibility of the gas valve. Regulating airflow is handled by dampers and blowers, monitoring temperature is managed by thermostats and temperature sensors, and the ignition of the burner is typically performed by an ignitor or pilot light. Therefore, controlling gas flow is the definitive function of the gas valve.