What component de-energizes the gas valve in case of furnace overheating?

The component that de-energizes the gas valve in case of furnace overheating is the limit control. This device plays a crucial role in the safety and proper operation of gas furnaces.

Limit controls are designed to monitor the temperature within the furnace and ensure it does not exceed safe operating levels. If the temperature rises beyond a predetermined threshold, the limit control will interrupt the operation by opening the circuit to the gas valve, effectively shutting off the gas supply and preventing further combustion. This action helps to prevent furnace damage, associated hazards, and ensures the system operates within safe parameters.

Understanding the function of the limit control is essential for maintaining safe heating system operations and recognizing the importance of preventive measures against overheating in forced-air and hot-water heating systems.