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

Which component will shut down the oil burner if there is ignition failure?

1. Stack switch

2. Vaporstat

3. Boiler steam pressure gauge

4. Smoke detector

The correct answer is: Stack switch

The stack switch is designed to monitor the flue gases produced by the combustion process in a boiler. If there is an ignition failure, the combustion will not be occurring as intended, leading to a change in the flow or temperature of the flue gases. The stack switch can detect these abnormalities and will shut down the oil burner to prevent dangerous conditions, such as the accumulation of unburned fuel or a lack of proper ventilation. This safety feature is critical for ensuring the safe operation of the boiler and preventing accidents or hazardous situations. In contrast, while a vaporstat monitors the pressure of steam in the boiler and a smoke detector is focused on detecting smoke as an indicator of incomplete combustion or a fire hazard, they do not specifically detect ignition failure. The boiler steam pressure gauge serves to indicate the pressure level within the boiler but does not function to shut down the burner. Each of these components serves important roles, but the stack switch is the specific device designed to respond to ignition failures.