🔍 Key Concepts

• Hydraulic symbol meanings – note the spring, arrow, and pilot (dashed) lines drawn at valve "D" • How an unloading valve is usually located in a circuit (relative to the pump and reservoir) versus a relief valve • Where a counterbalance or sequence valve is normally placed in relation to the actuator/load line

💭 Think About

• Look at the flow path that valve "D" will connect when it opens – is it mainly sending pump flow somewhere else, protecting against over‑pressure, or holding a load? • Trace the dashed pilot lines going to valve "D". What pressure point in the system is controlling it, and what does that suggest about its job? • Compare the position of valve "D" in the system to where you would expect a counterbalance valve near a cylinder versus a pressure‑control valve near the pump

✅ Before You Answer

• Verify which ports of valve "D" are connected to the pump discharge, to tank, and to any pilot line • Check whether any valve in the circuit is obviously protecting the system from over‑pressure – that one would be acting as a relief valve, so eliminate that choice from valve "D" • Confirm whether valve "D" is directly supporting the load-holding function at the actuator (typical of a counterbalance valve) or is mainly managing pump output (typical of an unloading or sequence valve)