🔍 Key Concepts

• Control of refrigerant flow to individual boxes or rooms • Relationship between solenoid valves and expansion valves in multi-box systems • Purpose of solenoid valves in automatic temperature control and pump-down operations

💭 Think About

• In a system with multiple boxes (freeze, produce, dairy, thaw), how does the system stop cooling one box while keeping the others operating? Where must a valve be placed to allow that? • Think about the normal direction of refrigerant flow: compressor → condenser → receiver → expansion valve → evaporator → back to compressor. At what point in this path would an electrically controlled shutoff be most useful for each box? • What is the difference between a line that serves the entire system and a line that serves each individual evaporator? Where should an on/off control be installed to control each box separately?

✅ Before You Answer

• Identify where liquid refrigerant is present at high pressure versus low pressure; solenoid valves commonly control high-pressure liquid going to each evaporator. • Confirm which locations in the options would affect all boxes at once versus those that can control each box individually. • Verify that the chosen location allows proper operation of the expansion valve and does not interfere with its sensing and throttling function.