How do you know if a hydraulic relief valve is bad?

 A damaged relief valve for hydraulics typically manifests as irregular system pressure, high heat production, slow or irregular actuator movement, strange chattering or whining sounds, and even fluid discharge while the valve is operating under normal loads. These indicators point to damaged seats, weak or broken springs, dirt stuck in the valve, or an inoperative poppet that does not seal properly. To confirm the diagnosis, you must isolate the valve, testing the readings of pressure against the setpoint of the system using a calibrated gauge and then examining the internals of the valve for signs of wear, scoring, or any other debris.
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