What is the function of a stack switch or stack relay?

The function of a stack switch or stack relay is to detect flame and control electrical contacts for burner operation. This component is crucial in a heating system as it ensures that the burner operates only when a proper flame is present, thus preventing unsafe conditions such as unburned fuel accumulation. The stack switch monitors the combustion gases and detects whether a flame is present; if the flame goes out or fails, the stack switch will interrupt the burner operation, shutting down the system to avoid hazardous situations.

This safety measure is essential in maintaining the efficiency and safety of heating appliances as it directly relates to the combustion process and overall burner control. By ensuring that the burner operates under safe conditions, the stack switch contributes significantly to the safety and reliability of oil heating systems.