Red Seal Oil Heat System Technician Practice Exam

What distinguishes a two-pipe oil supply system from a single-pipe system?

1. A two-pipe system returns unused oil back to the tank

2. A single-pipe system uses a larger diameter pipe

3. A two-pipe system requires more maintenance

4. A single-pipe system is always more efficient

The correct answer is: A two-pipe system returns unused oil back to the tank

In a two-pipe oil supply system, the distinguishing characteristic is that it features a return line that channels unused oil back to the oil tank. This setup allows for a continuous flow of oil, which means that any oil that does not get consumed by the burner is efficiently returned to the tank instead of being left in the system. This design minimizes the risk of oil stagnation and potential clogs, ensuring that the burner receives a steady and reliable supply of oil for combustion. In contrast, a single-pipe system operates with only one pipe that serves both to supply oil to the burner and as a return. This can lead to situations where oil is left in the system, potentially causing issues such as blockage or requiring more frequent maintenance checks. The efficiency of oil use in a single-pipe system can be compromised, as any excess oil can remain stagnant in the line. Therefore, the two-pipe system's design of returning unused oil is pivotal to its operation, making it a vital distinction compared to a single-pipe system.