E13 error; machine overheats or shuts down during long brewing or multiple cycles.

Safety: Unplug the machine and let it cool completely before inspection.

• Check ventilation: Ensure the coffee maker has adequate space around it (at least several centimeters on all sides) and that vents are not blocked by cabinets or objects.
• Clean vents: Use a soft brush or vacuum to remove dust from ventilation grilles.
• Descale thermoblock: Run a full descaling cycle to improve heat transfer and reduce overheating.
• Inspect cooling fan: If your Zwilling model has an internal fan, remove the cover and check if the fan spins freely. Replace if seized or noisy.
• Check temperature sensors: Inspect and test NTC sensors and thermostats on the thermoblock as described for E01/E05. Replace if out of specification.