What is the purpose of the high limit control?

The high limit control is essential for ensuring safe operational conditions in a steam system. Its primary purpose is to sense steam pressure and, if the pressure exceeds a predetermined safe limit, to shut down the burner automatically. This action helps prevent potentially dangerous situations, such as overpressure conditions that could lead to equipment failure or catastrophic accidents. By enforcing limits on steam pressure, the high limit control contributes significantly to the overall safety and efficiency of the boiler system.

In contrast, monitoring and maintaining the water level in the boiler, controlling fuel flow, and monitoring combustion chamber temperature are critical but separate functions. Each of those tasks involves different controls and systems that serve distinct safety and operational purposes in managing the boiler and its performance.