crwdns2890332:0reservoir refilling from the machinecrwdne2890332:0When I selected a large mine (a B60) would pump about 6 ounces, and then the rest would flow back to the tank through the vent/overflow line. None of the regular repairs helped. I tried descaling, cleaning needles, banging it around every way conceivable, blowing air into both the holes on the vent, and removing and cleaning the top check valve. Then I took the bottom off and saw there is a simple check valve on the pump discharge. It has a rubber nipple in it which I pried out with tweezers after removing three screws and splitting the housing. There were blisters on the rubber nipple preventing it from operating properly. I punctured the top layer of rubber on the blisters from the outside with a sewing needle and squeezed out the trapped water. Reassembled the unit and now it is working fine.