Models covered
On the Kärcher FC7, a fill-water warning with a visibly full fresh-water tank does not automatically mean that the tank or pump has failed. The official manual identifies two user-checkable causes: the sensor in the tank holder can be dirty, and distilled water may not be detected correctly. Switch the cleaner off and remove the fresh-water tank. Inspect the tank for cracks or leakage, then clean only the visible holder sensor gently with a clean cotton swab; do not pour liquid into the holder or probe the wiring.
Fill with ordinary tap water and the approved detergent dose, avoiding distilled water, and seat the tank completely. Restart once and allow a short moment for the indication to update. If the warning remains, the sensor circuit needs qualified service. This guide deliberately does not link an unverified tank or sensor because the catalog does not prove an exact FC7 replacement for this symptom.
Before checking Kärcher FC 7 Cordless
- Keep the tank holder and electrical contacts dry; do not scrape the sensor, bridge contacts or dismantle the cleaner.
What this symptom can mean on Kärcher FC 7 Cordless
4 checks for Kärcher FC 7 Cordless, starting with Power off and remove tank
- Power off and remove tank
Switch off, disconnect the charger or plug, lift out the fresh-water tank and place it on a dry surface.
- Clean the visible sensor
Use a clean dry cotton swab on the sensor in the holder without pressing hard or introducing fluid.
- Use tap water
Empty distilled water if present, fill to the mark with tap water and only the approved cleaner quantity.
- Seat and restart once
Push the tank fully home, power on and wait briefly; repeated cycling will not repair a faulty sensor.
When to stop checking Kärcher FC 7 Cordless
- Stop if the tank leaks, contacts are wet or corroded, the warning remains after the documented checks, or the cleaner behaves unpredictably.
Next step
After checking Kärcher FC 7 Cordless: repair, part or service?
Treat “Kärcher FC7 fill-tank light stays on with a full tank” as a condition to verify. The first of the 4 documented checks is “Power off and remove tank”; its result guides what follows.
Finish the checks before buying
Complete the Kärcher FC 7 Cordless sequence, starting at “Power off and remove tank”. When the symptom clears without a remaining alert, no replacement is indicated.
Arrange a diagnosis if a stop condition appears
Do not condemn Kärcher FC 7 Cordless from “Kärcher FC7 fill-tank light stays on with a full tank” alone. Stop at the warnings above and let a qualified diagnosis establish whether repair remains safe and proportionate.
Sources used
- Kärcher — The official FC7 manual states that a full-tank warning can result from a dirty holder sensor or distilled water and instructs cleaning the sensor with a cotton swab.
Last checked: 30 August 2026