🔍 Key Concepts

• Function of a pressure-relief valve in a hydraulic system • Difference between setting system maximum pressure vs controlling branch/actuator pressure • How a hydraulic system protects components from overpressure

💭 Think About

• Ask yourself: Which valve is normally adjusted to a set PSI so that, if pressure rises above that point anywhere in the system, fluid is diverted back to tank? • Which of these valves is concerned with overall system safety, rather than controlling motion of a cylinder or pressure in one part of the circuit? • Think about which valves are mainly for flow control and motion control (holding a load, unloading a pump, lowering pressure to a sub-circuit) instead of protecting against overpressure.

✅ Before You Answer

• Identify which option is specifically designed to limit maximum system pressure and protect against overpressure. • Eliminate any valve whose main purpose is load holding, energy saving, or lowering pressure only in a secondary circuit. • Verify in your hydraulics notes which valve is typically set to the system’s highest safe pressure rating.