An exemplary refill unit for a foam dispenser comprises a container for holding foamable liquid, a foam pump secured to the container wherein the foam pump includes a housing, a molded multi-chamber diaphragm wherein the molded multi-chamber diaphragm comprises a liquid pump chamber and three air pump chambers, an inlet valve and an outlet valve. A mixing chamber is included and located downstream of the outlet valve for mixing foamable liquid from the liquid pump chamber with air from each of the three air pump chambers. In addition, a foam cartridge and an outlet for dispensing foam are also included.