🔍 Key Concepts

• Compare how many supply and return lines are shown for hot and chilled water in each diagram • Notice whether hot and chilled water come from the same system or from separate systems in the four-pipe layout • Think about what happens if one space needs heat while another space needs cooling at the same time

💭 Think About

• In the four-pipe diagram, what is being supplied to Zone 1 versus Zone 2, and how could they be different at the same time? • In the two-pipe system, if you switch the HW/CW system from heating to cooling, what happens to all zones on that loop? • Looking at the piping, which option would increase flexibility of temperature control in different zones, and which options are just talking about more or fewer pipes?

✅ Before You Answer

• Verify whether the four-pipe system has separate supply and return for hot water and separate supply and return for chilled water • Confirm if the two-pipe system can carry only one type of water (hot or chilled) at a time to all zones • Make sure the choice you pick describes an operational advantage, not just a statement about pipe quantity without explaining control or flexibility