Which component reseats a pressure relief valve when fluid drops below its settings?

The component responsible for reseating a pressure relief valve when the fluid pressure drops below its preset level is the spring. The spring provides the necessary force that holds the valve closed during normal operating conditions. When the pressure in the system exceeds the set limit, the pressure relief valve opens, allowing fluid to escape and thus preventing damage to the system. Once the pressure falls back below the preset threshold, the spring pushes the valve back into its closed position, effectively reseating it.

This self-regulating function is crucial for maintaining system integrity and safety, ensuring that the excess pressure is released while also allowing the system to return to its normal operational state when pressure levels are within safe limits. The other components, while vital to the overall function of the valve, do not serve this specific purpose. For instance, the poppet acts as the sealing element that opens and closes, the adjusting screw is primarily used for setting the desired pressure limit, and the orifice is part of the flow path but does not contribute to the reseating action.