What is the purpose of a limit switch in a furnace?

The role of a limit switch in a furnace is to monitor temperature. This component is crucial for the safe operation of the heating system. The limit switch is designed to shut off the furnace if it detects that the temperature inside the heat exchanger exceeds a predefined limit, which helps prevent overheating and potential damage to the furnace. By doing so, it protects both the appliance and the home from unsafe conditions such as fires or equipment failures.

The limit switch's function is specifically tied to temperature measurement and control, ensuring that the appliance operates within safe parameters. This thermal monitoring aspect is key to maintaining efficient and safe furnace operation.

In contrast, other components or systems in the furnace handle tasks such as gas flow regulation or fan speed control, which are distinct from the monitoring function of the limit switch. Additionally, igniting the burners is performed by the ignition system, not by the limit switch, which further delineates its unique purpose.