🔍 Key Concepts

• Swing-check valve symbol on piping diagrams (how it looks compared with a globe or gate valve) • Difference between a check valve (one-way flow) and a manually operated isolation valve • Location in the system where backflow prevention would be especially important

💭 Think About

• Look at items 1–4 and decide which symbol shows a valve that allows flow in only one direction, rather than a hand- or motor-operated shutoff valve. • Ask yourself: which numbered component would protect the pump or equipment from reverse flow when the pump is secured? • Compare the valve symbols: which one shows an internal moving disc or flap rather than just an open/closed block?

✅ Before You Answer

• Verify which of the numbered items includes a check-valve arrow or flap inside the valve body symbol. • Confirm that the selected item is not labeled with a motor operator (M) or clearly used as a simple shutoff valve. • Check that the chosen valve is placed where reverse flow would be undesirable, such as on the discharge or suction side of the pump or near the manifold.