What is the normal limit control circuit voltage of a heating system?

In a typical heating system, particularly those involving oil heat or similar applications, the normal limit control circuit voltage is designed to ensure safety and proper operation. The standard voltage for limit control circuits in most residential and light commercial heating systems is 24 volts. This lower voltage level is preferred to reduce the risk of electrical shock and enhance user safety. Limit controls monitor the temperature within heating systems and act to prevent overheating by shutting down the system if unsafe conditions arise.

While other voltage levels like 120, 240, or 480 volts may be used for different components within the overall heating system (such as power supplies for larger equipment), they are not used for limit control circuits specifically. Instead, those higher voltages are associated with main power supplies or specific high-demand components, not the safety mechanisms that limit the temperature. By using 24 volts for limit controls, manufacturers prioritize safety and functionality for ongoing operation of heating systems.