🔍 Key Concepts

• Trace the control lines from each thermostat symbol (T) to see which valve or damper it actually operates in the diagram. • Understand the role of a terminal reheat system: central unit conditions air to a common duct temperature, and local reheaters adjust individual room temperatures. • Note the difference between the steam preheater (P) coil near the outside air intake and the hot-water reheater (R(W)) located at each room branch.

💭 Think About

• Look at the thermostat shown in each stateroom branch: is it sensing room air or duct air, and which valve does it modulate? • Follow the steam line to the preheater coil: do you see any room thermostats tied into that control loop, or is it controlled by something else in the main unit? • In summer operation, would it make sense for the main supply duct air to be warmer than the desired room temperatures if you still want cooling available to every room?

✅ Before You Answer

• Verify which thermostat symbol in the legend represents a room thermostat versus a duct thermostat, and match those to the illustration. • Confirm which component actually controls dry bulb room temperature in each stateroom: the central preheater/cooler or the local hot-water reheater coil and valve. • Check whether the preheater steam valve is shown as being controlled by a room thermostat or by a thermostat located in the main duct/outdoor-air section.