🔍 Key Concepts

• Direct expansion refrigeration system control sequence • Difference between pressure-operated and temperature-operated controls • What actually starts and stops the compressor motor in multi-box systems

💭 Think About

• Ask which device actually senses suction or discharge conditions and opens/closes an electrical circuit to the compressor motor. • Consider which components are used mainly for refrigerant flow control and which are used primarily for safety protection or on/off cycling. • Think about what happens to suction pressure when the boxes reach their set temperature and how that affects the compressor.

✅ Before You Answer

• Identify which choice is a motor control safety vs a flow control valve. • Determine which device responds directly to low side (suction) pressure in a direct expansion system. • Verify which device is normally wired into the compressor starter circuit for automatic cycling.