🔍 Key Concepts

• Front-seated vs back-seated position on a refrigeration/service valve and what happens to flow in each position • How the valve stem and sealing face (seat) line up in a fully front-seated position • The difference between fully open, mid-position (cracked), and fully closed as shown in cross-section illustrations A, B, and C

💭 Think About

• In which illustration is the valve stem driven all the way toward the line connection so that its sealing face is tightly against the front seat, blocking flow past that point? • Compare how much of the valve stem thread is visible in A, B, and C—where would it be when the valve is turned fully in (closed toward the front)? • Look at the passage the refrigerant would flow through. In which figure is that passage clearly blocked by the valve seat, rather than partially open or fully open?

✅ Before You Answer

• Verify which end of the valve body is the front seat (toward the line connection) and which is the back seat (toward the compressor/packing)** • Check that in the fully front‑seated position, the flow path between the compressor side and the line side is completely closed at the front seat • Confirm that the illustration you choose shows no visible gap between the valve’s sealing surface and the front seat, indicating a fully seated condition