New York Low Pressure Boiler Certificate of Fitness (COF) Practice Test

What is the function of a stack switch in a boiler system?

1. Control water levels

2. Regulate fuel flow

3. Detect smoke

4. Monitor heat in the smoke stack

The correct answer is: Monitor heat in the smoke stack

A stack switch plays a crucial role in boiler safety and efficiency by monitoring the temperature of the smoke in the stack. This function is vital for detecting whether the boiler is operating under safe conditions. If the temperature exceeds a predetermined limit, it can indicate that the combustion process is not functioning correctly, potentially leading to hazardous situations such as overheating or even a fire. By monitoring heat in the smoke stack, the stack switch ensures that the boiler operates within safe temperature parameters, which helps to prevent accidents and maintain optimal performance. In contrast, controlling water levels is managed by different devices like water level controls or alarms, while regulating fuel flow involves components such as fuel valves or controls that specifically manage the input of fuel to the burner. Detecting smoke is typically handled by smoke detectors rather than a stack switch, which is primarily concerned with the temperature of the exhaust gases rather than the presence of smoke itself.