🔍 Key Concepts

• In a thermal fluid heating oil system, expansion happens where the oil can safely change volume as temperature changes without overpressurizing the system. • Deaeration (removal of air/gases) is usually done at a high point in the system where gases naturally rise and can be vented. • Look for the component that is connected both to the main circulating line and to a vent/overflow line leading to or from the top of the system.

💭 Think About

• On the illustration, which numbered component is located at or near the highest elevation and appears designed to collect any air or vapors that rise from the system? • Which component has piping that suggests it can relieve excess volume or pressure, such as a connection to an overflow or vent line separate from the main circulation loop? • Compare the functions of the heater, pump, storage/return tank, and any overhead vessel—which one would reasonably allow the oil to expand and air to escape without affecting normal circulation?

✅ Before You Answer

• Verify which numbered item is positioned at the top of the system and has a line going upward that could serve as a vent or overflow. • Confirm that the component you choose is not the heater, circulator pump, or main storage/return tank—those have different primary functions. • Make sure the component you select is one that could be partially filled with fluid and space for vapor, consistent with an expansion/deaeration tank.