Expansion tank holds up to how many gallons?

• A. Radiator Pressure cap
• B. LP
• C. Expansion tank
• D. Y strainer

Answer: (C)

Expansion tanks are designed to hold extra water as the system heats up. In a closed heating or hot-water system, water expands when it warms, and the expansion tank provides a space (measured in gallons) to absorb that added volume. That makes the expansion tank the component that stores liquid, whereas the radiator pressure cap regulates pressure, the LP line isn’t a storage vessel, and a Y strainer is just a filter. So the only option that represents a container capable of holding gallons is the expansion tank. In actual systems, the exact gallons it holds depends on the design, typically a few gallons.