What function does a furnace limit switch serve?

• A. It increases airflow during heating
• B. It prevents the system from underperforming
• C. It shuts down burners to prevent overheating
• D. It regulates air quality in the furnace

Answer: (C)

The furnace limit switch plays a crucial safety role in heating systems. Its primary function is to monitor the temperature within the furnace and ensure that it does not exceed a designated safe level. When the temperature reaches a certain threshold, the limit switch activates and shuts down the burners. This action is essential in preventing overheating, which could lead to potential hazards such as fires or damage to the furnace components.

By activating at high temperatures, the limit switch acts as a safeguard, ensuring the system operates within safe limits. This function is critical for maintaining both the safety and efficiency of the heating system.