E7 displayed and the unit beeps when the dirty water tank is nearly empty or just refitted; suction will not start.

Safety first: Unplug the cleaner before removing tanks.

• Remove and reseat dirty tank: Take out the dirty water tank, empty and rinse it, then refit it firmly so it clicks into place. Ensure the lid is correctly locked.
• Check float movement: Open the dirty tank lid and locate the plastic float. Move it gently up and down; it should move freely and drop back under its own weight. Clean away soap residue or debris that may cause sticking.
• Inspect tank sensor area: On some models, a small tab on the tank actuates a microswitch in the base. Ensure the tab is not broken and that the switch lever moves freely.
• Test again: Plug in and try to start suction. If E7 remains, the tank sensor switch or the level-sensing circuit on the PCB may be faulty.
• Professional repair: Replacement of the dirty tank sensor switch or control PCB should be done by a technician.