What does the stack switch monitor in the oil burner system?

The stack switch in an oil burner system monitors the temperature of the flue gases as they exit the combustion chamber. This is crucial for ensuring that the oil burner operates efficiently and safely. When the flue gas temperature exceeds a certain setpoint, the stack switch can signal the burner to shut down, preventing overheating that could lead to a hazardous condition.

Monitoring the temperature in the flue gases also helps in assessing the efficiency of the combustion process and identifying any potential issues such as incomplete combustion or a malfunctioning burner. By measuring the temperature, the stack switch plays a vital role in maintaining safe operation conditions in the heating system.

The other options, while related to the operation of the oil burner system, do not pertain directly to the function of the stack switch. Fuel flow, combustion chamber light, and air pressure are monitored by different components within the system to ensure optimal performance and safety.