Dehumidifier displays E4 and stops; may beep repeatedly.

Safety: Disconnect from mains before opening the control panel or front cover.

Steps:

• Locate the humidity sensor: On many Olimpia Splendid dehumidifiers, the RH sensor is mounted near the air intake grille or behind the front panel, often on a small daughter board or as a plastic-encased sensor with a 3–5 wire harness.
• Visual inspection: Check for dust buildup on the sensor. If accessible, gently blow off dust with dry compressed air. Do not soak with water or harsh cleaners.
• Check connections: Ensure the sensor plug is fully seated on the main PCB or small sensor board. Look for corrosion or bent pins and clean with contact cleaner if needed.
• Functional test: If the unit allows manual continuous mode (no humidity setpoint), try switching to that mode. If E4 persists and the unit will not run, the sensor is likely defective.
• Replace the RH sensor: Obtain a compatible Olimpia Splendid humidity sensor assembly. Unplug the old sensor, remove any mounting screws or clips, and install the new one in the same position.
• Board replacement: If a new sensor does not resolve E4, the main control board may be faulty and should be replaced by a technician.