Red Seal Oil Heat System Technician Practice Exam

Which of the following components is designed to prevent backflow in oil piping?

1. Pressure relief valve

2. Check valve

3. Flow control valve

4. Air vent valve

The correct answer is: Check valve

The component specifically designed to prevent backflow in oil piping is the check valve. A check valve is a one-way valve that ensures fluid can only flow in a single direction, thereby preventing any reverse flow that could compromise the system's integrity. This is crucial in oil heat systems, as backflow can lead to contamination, system inefficiencies, or even leaks. The pressure relief valve, while important for regulating the system’s pressure by releasing excess pressure, does not serve the purpose of preventing backflow. Similarly, the flow control valve is used to manage the flow rate but does not inherently stop fluid from flowing backward. An air vent valve is used to release trapped air from the system and is not designed to manage flow direction. Understanding the specific functions of these valves helps clarify why the check valve is the correct choice for preventing backflow in oil piping.