Dryer stops, may show F04, sometimes accompanied by overheating or very hot cabinet surfaces

Safety first: Unplug the dryer. Internal metal parts and the heater housing can be extremely hot; allow the unit to cool fully before working.

• Clean airflow path: Remove and thoroughly clean the lint filter. Inspect the internal lint channel, rear exhaust duct, and wall vent for heavy lint buildup. Clean with a vacuum and brush.
• Access thermostats: Remove the rear panel to access the heater housing. Identify the high‑limit thermostat and cycling thermostat (small round devices with two terminals).
• Check for manual reset: Some Ariston high‑limit thermostats have a small reset button. If present, press it firmly until it clicks. Do not repeatedly reset without fixing airflow issues.
• Inspect wiring and mounting: Ensure thermostats are firmly attached to the heater housing and that wiring terminals are tight and not burnt.
• Replace faulty thermostat: If the thermostat is open circuit (tested by a technician) or visibly damaged, replace it with the correct Ariston‑specified thermostat.