🔍 Key Concepts

• Look closely at the direction of motion needed to CLOSE each valve element (pilot and main). "Seating" means the direction the plug moves to press against its seat. • Use the flow arrows (INLET to OUTLET) and the location of each valve seat to decide if the plug must move upward or downward to stop the flow. • In a self‑contained, internal‑pilot, piston‑operated valve, the pilot valve controls pressure on top of the main piston. How that control passage opens/closes depends on the pilot’s seating direction.

💭 Think About

• On the main valve, when it is fully CLOSED, is the plug pressed up against a seat that is above it or below it? From that, which way must the plug move to seat? • For the pilot valve, find the small plug and its seat in the upper control passage. When the temperature element causes the pilot to shut off flow, does the pilot plug move upward or downward to press against its seat? • Think about which side of each plug the upstream pressure acts on. In normal operation, should pressure tend to help close the valve or help open it? That clue helps you infer the seating direction.

✅ Before You Answer

• Identify the exact location of the main valve seat in the lower body and confirm whether the main plug moves up or down to contact it when closed. • Identify the pilot valve seat in the small control passage (around labels J and H) and verify whether the small pilot plug moves up or down to shut that passage. • Before choosing, restate to yourself: "Seating direction = direction of plug motion to close." Then match your observations to the choice that correctly combines both pilot and main seating directions.