🔍 Key Concepts

• Trace the liquid refrigerant line that feeds the chill box evaporator (labeled "J" or "K" depending on your drawing legend) and find the control valve located just upstream of the evaporator inlet. • Recall how a thermal expansion valve (TXV) is drawn: a throttling valve in the liquid line with a small capillary or sensing line running to the evaporator outlet or suction line. • Distinguish between a solenoid valve (electrically operated on/off valve, often shown with a coil symbol or "S") and a TXV (modulating valve controlled by a sensing bulb).

💭 Think About

• Start at the chill box coil and follow the inlet line backward until you reach the first control device that meters liquid refrigerant into the coil. Which number labels that valve? • Compare the symbols and numbers around the freezer evaporator and the chill box evaporator. Which number around the chill box matches the same type of valve used to meter flow into the other evaporator? • Look for the valve that has a small line leading from its top or side to the suction line or evaporator outlet—this indicates a thermostatic expansion valve rather than a simple shutoff or solenoid valve.

✅ Before You Answer

• Verify which evaporator in the drawing is the chill box, not the freezer, by looking at coil style and any temperature labels. • Confirm that the chosen component is in the liquid line, immediately ahead of the chill box coil, not in the suction return line. • Make sure the component you pick has the typical TXV symbol and sensing line, not the symbol used for a solenoid (often marked with an "S" nearby) or a hand-operated stop valve.