Remove the two Phillips screws from the pump manifold and lift it off the end of the pump, minding the two locking tabs near its base.

The pump used in the Barista utilizes the electromechanical properties of a solenoid to pump water up from the reservoir.

An iron core placed in the center of a cylindrical coil of wire is reciprocated back and forth through the coil when AC voltage is applied to it. Springs on either end of the core absorb its kinetic energy.

The core is attached to a plunger (outlined in green) that fits tightly into a cylinder on the pump manifold which creates the pumping action when the core moves back and forth.

The pressure difference between the inside of the cylinder and the water tank causes water to be drawn up from the reservoir into the pump, whenever the steam valve is opened, to assure the boiler is supplied with water.