Dehumidifier shows E3 and stops dehumidifying; compressor does not start.

Safety: Disconnect the Klarstein dehumidifier from mains before opening the housing.

• Locate humidity sensor: On many Klarstein models, the humidity sensor is mounted behind the front air inlet grille or on a small PCB near the control panel, exposed to room air.
• Visual inspection: Check for dust buildup, corrosion, or water staining on the sensor module. If heavily contaminated, gently clean with a soft brush and dry compressed air (do not soak).
• Check wiring: Ensure the sensor cable is not pinched by the front cover and that the connector is fully seated on the main PCB or sub-board.
• Functional test: If the unit allows, compare displayed humidity to a separate hygrometer. If readings are erratic or E3 appears intermittently, the sensor is suspect.
• Replace sensor module: Order a compatible Klarstein humidity sensor module for your exact model. Remove the old module (usually held by 1–2 screws or clips), transfer any gasket, and plug in the new sensor. Reassemble the front panel.
• Re-test: Power on and clear any error by unplugging for 1–2 minutes. If E3 persists with a new sensor, the main PCB may need replacement.