Unit displays E4 and does not start heating when hot water is demanded

Safety first: Turn OFF power at the breaker and close the cold water supply. Relieve pressure by opening a hot water tap.

Steps:

• 1. Clean inlet filter: Remove the cold water inlet filter screen (often at the inlet union). Rinse debris and reinstall.
• 2. Access flow sensor: Remove the front cover. The flow sensor is typically installed on the cold water inlet manifold and may have a small cable connected to the PCB.
• 3. Inspect and clean: Shut off water, remove the flow sensor body, and check the turbine or paddle for scale or debris. Clean gently with a soft brush; do not damage the turbine.
• 4. Check wiring: Ensure the flow sensor connector is fully seated on the PCB and wires are not broken or pinched.
• 5. Test operation: Reassemble, open water supply, and restore power. Open a hot tap and see if the unit recognizes flow (heating indicator should come on and E4 should clear).
• 6. Replace flow sensor: If the turbine does not spin freely or the sensor still does not register flow, replace the flow sensor assembly with an Electrolux-compatible part.

Professional help: If a new flow sensor does not resolve E4, the PCB input circuit may be faulty and should be diagnosed by a technician.