Which control prevents boiler overheating by stopping the burner at high temperature?

• A. Regulate flame
• B. Control pressure
• C. Schedule maintenance
• D. Prevent overheating

Answer: (D)

The automatic safety device that stops the burner when the boiler temperature reaches a preset high limit is the high-temperature limit control. It senses the heat and, if the temperature climbs too high, it interrupts the fuel supply to the burner, shutting it off to prevent overheating and potential damage or safety hazards. This happens independently of normal operation controls, providing a hard stop to protect the system.

Regulating the flame might adjust how hot the boiler runs, but it doesn’t impose a strict shutdown at a dangerous temperature. Controlling pressure ensures safe gas delivery, not temperature protection. Scheduling maintenance helps keep components in good shape, but it isn’t an automatic response to overheating.