Display shows E4 and the coffee maker beeps without starting the brew cycle.

Safety first: Unplug the coffee maker before removing the reservoir or accessing internal parts.

• Check reservoir outlet: Remove the water reservoir and inspect the outlet valve at the bottom. Clean any debris or coffee grounds and ensure the valve moves freely.
• Run a prime cycle: Fill the reservoir completely with water, reseat it firmly, then start a brew without coffee. If the pump is air-locked, it may take 1–2 attempts to start drawing water.
• Descale thoroughly: Use a 1:1 vinegar and water solution and run multiple brew cycles to dissolve internal scale. Pause mid-cycle for 15–20 minutes to let the solution soak in the lines.
• Listen to the pump: If you hear the pump humming but no water flows, the lines may still be blocked or the pump is weak. If there is no sound at all, the pump or its wiring may have failed and should be replaced.