What occurs if a stack switch activates?

When a stack switch activates, it indicates that there is an issue with the flue gases or the exhaust system of the heating appliance. The primary function of a stack switch is to monitor the venting of combustion gases; if it detects that the draft or flue gas temperature is not within safe limits, it will signal a shutdown of the burner. This action is a safety measure designed to prevent potential hazards such as the buildup of dangerous gases or even fire.

By shutting down the burner, the stack switch helps to ensure that the heating system operates safely and that any risks associated with improper venting are mitigated. In contrast, if the burner were to continue operating normally, it could lead to serious safety issues, making the activation of the stack switch a crucial aspect of safe HVAC operations.