🔍 Key Concepts

• Identify how control oil pressure and crankcase pressure are used in the device • Notice references to capacity control valve, unloader power element, and suction valve disc • Think about how large refrigeration compressors change their capacity without stopping the machine

💭 Think About

• What function does an unloader normally perform on a reciprocating compressor? • If the device is acting on the suction valves, is it more likely controlling room temperature directly, or changing how much gas the compressor actually pumps? • Which options describe a device that works mainly with oil pressure and crankcase pressure, rather than air temperature or humidity?

✅ Before You Answer

• Look for labels mentioning capacity control or unloader and match them to the answer choices • Confirm whether the diagram shows multiple unloader power elements that could be connected to several cylinders or heads • Verify whether any part of the drawing shows direct sensing of box temperature or humidity, or only pressures within the compressor system