An unloader check valve to be installed between a compressor and an air receiver comprising: an elongated valve body having an inlet end and an outlet end and a hole extending therethrough from said inlet end to said outlet end; CHECK VALVESan air bleed aperture extending through said valve body from a location in said hole; an unloader valve seal reciprocally mounted to move along a path within said hole; a valve seat assembly installed within said hole between said unloader valve seal and said outlet end of said valve body, said valve seat assembly having a circumference and a groove around said circumference, said groove of said valve seat assembly being adjacent said air bleed aperture when said valve seat assembly is installed in said valve body; said valve seat assembly having a plurality of raised unloader seating elements extending toward said inlet end of said valve body and in the path of said unloader valve seal, said unloader seating elements having at least a passage leading from said groove toward said inlet end of said valve body; said valve seat assembly having a check valve seat; a piston assembly mounted within said hole of said valve body, said piston assembly including a piston, a piston spring and a check valve seal, said piston spring normally biasing said piston toward said inlet end of said valve body to a first piston location when the compressor is turned off; Check Valvessaid piston assembly having a size and being located at a position within the hole which enables it to force said unloader valve seal away from said seating elements when said piston is at the first piston location, said check valve seal being positioned so as to contact said check valve seat when said piston is at the first piston location; Check Valves said unloader check valve permitting air to flow from between said unloader valve seal and said valve seat assembly through said at least a passage of said unloader seating elements to said groove of said valve seat assembly and permitting air to exit said unloader check valve through said air bleed aperture when said piston assembly holds said unloader valve seal away from said unloader seating elements; said piston being movable from the first piston location toward at least one downstream piston location further away from said inlet end of said valve body than the first piston location when the compressor is turned on to increase pressure within the air receiver; said piston assembly permitting said unloader valve seal to move toward and contact said unloader seating elements when said piston moves toward one of the downstream piston locations, thereby preventing air from passing from said inlet end of said body to said air bleed aperture when said piston is in one of the downstream piston locations; said piston being movable toward the first piston location by said piston spring when said air compressor forces decreasing amounts of air from the air compressor toward the air receiver a dampener connected to said valve body, said dampener being configured to dampen movement of said piston.

MORE NEW