Excessive frost or ice buildup on the back wall or around the evaporator; fan noise may increase.

Safety: Unplug the unit before defrosting or accessing internal components.

• Manual defrost: Remove all bottles, unplug the cooler, and leave the door open for 12–24 hours to melt all ice. Protect the floor from water.
• Check door gasket: Inspect for tears or gaps. Replace the "Door gasket" if it does not seal evenly.
• Clear drain: Locate the drain hole at the bottom of the evaporator area and clear any blockage with a soft brush or pipe cleaner.
• Test defrost heater and sensor (if equipped): After removing the rear internal panel, measure heater resistance and inspect the defrost sensor as described in the E4 entry.
• Replace faulty parts: Install a new "Defrost heater", "Defrost NTC sensor", or "Door gasket" as required.