Empty the dirty water tank.  Ensure the Dome lid is on Tank A and that the vacuum hose is connected to the dome lid spout and the other end to the wand pole.

Turn on the VAC button and check for vacuum suction. Disconnect vacuum hose from the dome lid and wand and check for vacuum suction from dome lid. Disconnect thick VAC hose and flush with water at high pressure.  Do the same with the floor wand.