Display shows E3 and the air fryer stops heating during a cook cycle.

Safety first: Unplug the unit and allow it to cool for at least 30 minutes. Surfaces and internal components may be very hot.

• Check ventilation: Ensure the Ultima Cosa air fryer has at least 5–10 cm clearance on all sides and that rear and top vents are not blocked by walls, cabinets, or objects. Clean any dust buildup from the vents.
• Clean interior: Remove the basket and drawer. Clean heavy grease buildup from the top interior and around the heating element with a non-abrasive cleaner once the unit is cool. Excess grease can overheat and trigger high-temp faults.
• Verify fan operation: Start a short cook cycle and listen for the fan. If the fan does not run, cancel the cycle, unplug the unit, and inspect the fan motor and wiring (see fan-related entries below). A non-running fan can cause E3.
• Inspect thermal cutoff: Access the top or rear panel to locate the high-limit thermostat or thermal fuse mounted near the heating element. Check for signs of overheating or discoloration. Some high-limit thermostats are auto-resetting; others are one-time fuses.
• Test components: With power disconnected, use a multimeter to check continuity across the high-limit thermostat or thermal fuse. An open reading on a non-resettable fuse means it must be replaced with the same temperature and rating.

If E3 recurs after cleaning vents and confirming fan operation, the control board may be misreading temperature and should be evaluated or replaced by a technician.