The subject matter of this specification can be embodied in, among other things, a check valve that includes a valve body having a bore and a seat along the bore, a fluid inlet at a first end of the bore, and a fluid outlet a second end of the bore, a stopper selectively movable along the bore to contact the seat, the bore being occluded when the stopper is in contact with the seat, a first bias member on a first side of the stopper within the bore, the first bias member providing a first bias force upon the stopper in a first direction, and a second bias member on a second side of the stopper within the bore, the second side being opposite the first side, the second bias member providing a second bias force upon the stopper in a second direction opposite the first direction.