New York Low Pressure Boiler Certificate of Fitness (COF) 2025 – 400 Free Practice Questions to Pass the Exam

The correct answer, which identifies the device that shuts down an oil burner in the absence of air for combustion, is the vaporstat. The vaporstat is a safety device that detects pressure levels of the vapor within the system. If it senses that the pressure falls below a certain threshold, typically due to inadequate combustion air, it will engage to shut down the oil burner to prevent unsafe conditions.

Understanding the function of the vaporstat is crucial, as it plays a vital role in ensuring that the combustion process occurs safely and efficiently. By shutting down the burner when there is insufficient air, it helps to prevent the potential for hazards such as incomplete combustion, which could lead to the production of harmful gases.

In contrast, a low water cutoff is designed to prevent a boiler from operating without sufficient water, a vaporstat is concerned specifically with the combustion process. A stack switch monitors the flue gas flow and will shut off the burner if it detects that the flue gases are not being vented correctly, which is not specifically tied to combustion air supply. An aquastat regulates the temperature of the water in the boiler and does not have a direct function related to combustion air. Each device serves a unique purpose in maintaining the safe operation of a boiler system,