A refrigerant valve for integration into a refrigeration system, the valve, comprising: a valve body 11; a piston and an adapter plate; the adapter plate comprising a plurality of openings formed in a bottom surface of the adapter plate for communication with the valve body when the adapter plate is removably connected to the investment-cast stainless-steel valve body; the investment-cast, stainless steel valve body comprising a valve inlet, a valve outlet, and a main body, the main body comprising a valve body bore, a flow chamber separated by a web projecting from the valve body bore to define a distal end, a main valve port adjacent the flow chamber, an inlet pressure port, and an outlet pressure port; wherein the inlet pressure port provides operative communication between the valve inlet and the adapter plate and the outlet pressure port provides operative communication between the adapter plate and the valve outlet, so that the adapter plate functions to control movement of the piston with respect to the main valve port; wherein, the piston comprises an upper seal configured engage the valve body bore; and characterized in that: - the valve body is an investment-cast, stainless-steel valve body; - the valve inlet and the valve outlet each comprise a respective flangeless distal and (210,212) configured, as cast, with an unmachined, weldable rim for integration without mechanical connections in a leak-free configuration; and - the piston comprises a lower seal configured to selectively engage the main valve port to stop the flow of the refrigerant fluid a valve body 11; a piston and an adapter plate; the adapter plate comprising a plurality of openings formed in a bottom surface of the adapter plate for communication with the valve body when the adapter plate is removably connected to the investment-cast stainless-steel valve body; the investment-cast, stainless steel valve body comprising a valve inlet, a valve outlet, and a main body, the main body comprising a valve body bore, a flow chamber separated by a web projecting from the valve body bore to define a distal end, a main valve port adjacent the flow chamber, an inlet pressure port, and an outlet pressure port; wherein the inlet pressure port provides operative communication between the valve inlet and the adapter plate and the outlet pressure port provides operative communication between the adapter plate and the valve outlet, so that the adapter plate functions to control movement of the piston with respect to the main valve port; wherein, the piston comprises an upper seal configured engage the valve body bore; and characterized in that: - the valve body is an investment-cast, stainless-steel valve body; - the valve inlet and the valve outlet each comprise a respective flangeless distal and (210,212) configured, as cast, with an unmachined, weldable rim for integration without mechanical connections in a leak-free configuration; and - the piston comprises a lower seal configured to selectively engage the main valve port to stop the flow of the refrigerant fluid - the valve body is an investment-cast, stainless-steel valve body; - the valve inlet and the valve outlet each comprise a respective flangeless distal and (210,212) configured, as cast, with an unmachined, weldable rim for integration without mechanical connections in a leak-free configuration; and - the piston comprises a lower seal configured to selectively engage the main valve port to stop the flow of the refrigerant fluid