Miele Dryer Error Code F66

F66 means the temperature sensor at the heater bank has detected a temperature above 338°F (170°C), indicating that airflow through the dryer is insufficient. The most common cause is a clogged lint filter, dirty heat exchanger, or blocked exhaust vent. The dryer stops operation to prevent overheating damage or a fire hazard. Cleaning the air path components is the recommended first step.

No, you should not continue operating the dryer while F66 is active. The error indicates that heat is building up beyond safe limits around the heater bank, which poses a risk of component damage and potentially a fire. The dryer's control system has already shut the unit down as a precaution, and it should remain out of service until the underlying airflow restriction is resolved.

If the fault is caused entirely by lint and debris buildup, the repair cost can be minimal, primarily your time to clean the filters and heat exchanger. If a component such as the heater bank temperature sensor requires replacement, parts and labor costs from a qualified technician could range from $150 to $400 or more depending on your location and the extent of any additional damage caused by the overtemperature condition.

Start by cleaning all lint filters, including the door lint filter and the fill ring lint filter. On condenser models, remove and rinse the heat exchanger under running water to clear accumulated lint from the fins. On vented models, inspect and clean the exhaust duct and exterior vent grille. Once all air paths are clear, run the dryer again to see if the error clears.

A reset may temporarily clear the error code, but the code will return if the underlying cause has not been addressed. Because F66 is triggered by a real temperature measurement exceeding a set threshold, the sensor will continue reporting the condition as long as the airflow restriction remains. Clean all air path components before attempting any reset.