An irrigated medical device, including an inlet tube configured to receive an irrigation fluid from a pressurized fluid source, at least first and second outlet tubes configured to deliver the irrigation fluid to respective outlets of the device, a manifold containing a chamber coupled between the inlet tube and at least the first and second outlet tubes, and a ball including a magnetic material contained inside the chamber. The irrigated medical device also includes a magnetic field generator disposed outside the chamber and configured to generate a variable magnetic field within the chamber so as to move the ball between at least a first position in which the first outlet tube is blocked, a second position in which the second outlet tube is blocked, and a third position, in which neither of the outlet tubes is blocked.