A valve for bidirectional fluid flow comprising: a housing providing a first and second port communicating with an internal housing volume; an elastomeric disk positioned between the first and second port in the internal housing volume, the elastomeric disk retained against the housing within an annular region of the elastomeric disk between a central region and an outer peripheral region so that the central region and outer peripheral region are free to move with respect to the housing; the housing providing a first valve seat engaging the outer peripheral region of the elastomeric disk when the elastomeric disk is in a relaxed state and having a second valve seat engaging the central region when the elastomeric disk is in a relaxed state; the housing further providing first flow channels leading from the first port to the elastomeric disk for receiving and conducting the fluid flow and second flow channels leading from the second port to the elastomeric disk for receiving and conducting the fluid flow, characterized in that the first flow channels lead the fluid flow from the first port to the elastomeric disk so that the fluid flow presses the elastomeric disk against the second valve seat and presses the elastomeric disk away from the first valve seat when pressure of the fluid at the first port is greater than pressure at the second port allowing flow from the first port to the second port; and the second flow channels lead the fluid flow from the second port to the elastomeric disk so that the fluid flow presses the elastomeric disk against the first valve seat and to lift the elastomeric disk away from the second valve seat when pressure of the fluid at the second port is greater than pressure at the first port allowing flow from the second port to the first port. a housing providing a first and second port communicating with an internal housing volume; an elastomeric disk positioned between the first and second port in the internal housing volume, the elastomeric disk retained against the housing within an annular region of the elastomeric disk between a central region and an outer peripheral region so that the central region and outer peripheral region are free to move with respect to the housing; the housing providing a first valve seat engaging the outer peripheral region of the elastomeric disk when the elastomeric disk is in a relaxed state and having a second valve seat engaging the central region when the elastomeric disk is in a relaxed state; the housing further providing first flow channels leading from the first port to the elastomeric disk for receiving and conducting the fluid flow and second flow channels leading from the second port to the elastomeric disk for receiving and conducting the fluid flow, characterized in that the first flow channels lead the fluid flow from the first port to the elastomeric disk so that the fluid flow presses the elastomeric disk against the second valve seat and presses the elastomeric disk away from the first valve seat when pressure of the fluid at the first port is greater than pressure at the second port allowing flow from the first port to the second port; and the second flow channels lead the fluid flow from the second port to the elastomeric disk so that the fluid flow presses the elastomeric disk against the first valve seat and to lift the elastomeric disk away from the second valve seat when pressure of the fluid at the second port is greater than pressure at the first port allowing flow from the second port to the first port.