Which device is used to prevent overheating by detecting an over-temperature condition and then cutting fuel supply?

Which device is used to prevent overheating by detecting an over-temperature condition and then cutting fuel supply?

• A. Flow switch
• B. High limit controls
• C. Low water cutoff switch
• D. Pressurization

Answer: (B)

The main idea here is a safety control that monitors the system’s temperature and automatically stops fuel delivery if things get too hot. High limit controls are designed for this purpose: they sense the temperature (in the heat exchanger or flue area) and, once a preset limit is reached, they interrupt the fuel supply to prevent overheating and potential damage or danger. Flow switches, on the other hand, check that there is adequate gas and air flow before the burner stays lit, not the temperature. A low water cutoff switch protects boilers by shutting off fuel if the water level is too low, preventing dry heating. Pressurization concerns the pressure of the combustion air or venting system, not temperature-based shutoff.

The main idea here is a safety control that monitors the system’s temperature and automatically stops fuel delivery if things get too hot. High limit controls are designed for this purpose: they sense the temperature (in the heat exchanger or flue area) and, once a preset limit is reached, they interrupt the fuel supply to prevent overheating and potential damage or danger.

Flow switches, on the other hand, check that there is adequate gas and air flow before the burner stays lit, not the temperature. A low water cutoff switch protects boilers by shutting off fuel if the water level is too low, preventing dry heating. Pressurization concerns the pressure of the combustion air or venting system, not temperature-based shutoff.