🔍 Key Concepts

• Potable hot water circulation on ships and why water sitting in pipes is a problem • Difference between temperature control vs pressure/overflow control in a domestic hot water system • Purpose of a recirculation (return) line in keeping distant fixtures usable

💭 Think About

• Imagine a sink or shower at the far end of the vessel. What happens to the water in the pipe between uses if there is no recirculating line? • Which choice directly addresses what happens to the temperature of water in long runs of pipe when there is low or no usage? • Look at each option and ask: does this sound like something to do with hot water delivery and comfort, or with tank protection/pressure behavior?

✅ Before You Answer

• Identify which options deal mainly with tanks and pressure rather than the condition of water in the distribution piping • Think about which option explains why you can get hot water quickly at a remote tap without waiting a long time • Confirm which choice clearly ties the recirculation line to maintaining a consistent condition at all outlets, not just at the tank