Reciprocating Compressor valves are usually automatic and open and close by:

Reciprocating compressor valves typically function automatically by responding to pressure differences within the compressor. When the pressure in the cylinder rises above the pressure in the intake manifold (or other chamber), this pressure difference causes the valve to open. Conversely, when the piston moves back down, reducing the cylinder pressure, the valve closes due to the higher pressure in the intake. This mechanism ensures that the valve opens and closes at the appropriate times during the compression cycle, allowing for efficient operation of the compressor.

The action of a poppet valve involves components that may be used in other types of systems but does not explain the automatic operation specific to reciprocating compressor valves. Similarly, the movement of the piston covering or uncovering ports is not the primary mechanism for valve operation, as the valve's action is driven by the pressure differential rather than the piston positioning alone. Lastly, the operation of an air solenoid valve pertains to electrically controlled systems and does not relate to the passive mechanism employed in typical reciprocating compressor valve actions.