🔍 Key Concepts

• Typical layout of a fuel oil system supplying burners on a marine boiler • Names and functions of valves near the burner: isolation, control, and safety shutoff • Difference between valves on the supply line versus return line

💭 Think About

• Think about which valve would be used to isolate the fuel supply line right before it reaches the burner control valve. • Ask yourself: which of these names sounds like an upstream shutoff on the main fuel supply header, not a control or adjustment at the burner air/fuel end? • Consider where a return line would be located in the system and whether that would normally connect between the header and the burner valve.

✅ Before You Answer

• Identify which option refers to a valve on a return line, not the supply line, and set that aside. • Decide which term is commonly used for a main isolating valve on a branch line from a header to a piece of equipment. • Confirm which term among the choices is associated with air/fuel mixing or burner air control, and eliminate it for a fuel oil line shutoff position.