🔍 Key Concepts

• Study the flow path from the INLET (II) to the OUTLET (III) and identify which part actually opens the passage for water to move. • Think about the cause‑and‑effect sequence: motion of the handle (E), movement of the pilot/diaphragm area (C), and position of the main valve element (A). • Consider how a diaphragm-operated valve works: pressure above and below the diaphragm, a pilot passage (H), and how changing that pressure difference makes the diaphragm move.

💭 Think About

• Which single component’s position physically separates or connects the inlet chamber to the outlet chamber? Trace the blue shaded areas and the seating surface. • If the handle (E) is moved but the main closure element does not change position, would water actually flow? What if the diaphragm moves but the closure element stays seated? • Are some of the answer choices describing causes and others describing the final condition that must exist for flow?

✅ Before You Answer

• Identify the exact sealing surface that blocks flow from II to III in the ‘no‑flow’ condition. • Verify which labeled part is in direct contact with that sealing surface when the valve is shut (critical). • Decide whether water can flow if that sealing surface remains closed, even if the other parts move as described.