What does a high limit control in a boiler prevent?

A high limit control in a boiler is designed primarily to prevent overheating. This safety device monitors the temperature of the water or steam within the system and is set to a specific upper limit. When the temperature exceeds this predetermined level, the high limit control will automatically shut the boiler down or disable the burner, ensuring that the system does not reach dangerous temperatures that could lead to equipment damage or safety hazards.

Understanding the function of a high limit control is critical for maintaining safe operation in heating systems. It acts as a crucial safeguard against the potential for catastrophic failures due to excessive heat, which could also cause burns or other hazards in an environment where the boiler operates. Other options like low pressure, high humidity, or gas leaks are governed by different controls or safety mechanisms within the HVAC system, and are not the primary focus of the high limit control’s function.