Bosch Dryer Error Code E:20b0

Error code E:20b0 on a Bosch dryer indicates a fault in the main heating circuit caused by restricted airflow through the system. This code is the hex-format equivalent of E:167 and is triggered when the dryer's sensors detect inadequate heat dissipation or abnormal temperature behavior in the heating loop. The two primary causes are a blocked lint filter preventing air from moving freely through the drum and exhaust path, or a frozen evaporator (heat exchanger covered with ice) in heat pump dryer models, which similarly restricts airflow and disrupts the refrigerant-based heating cycle.

In heat pump dryers, the evaporator absorbs moisture from the drum air and can develop ice buildup if the unit is operated in very cold ambient conditions, typically below 5 degrees Celsius. When ice covers the evaporator coils, airflow is choked off and the heating circuit cannot maintain proper operating temperatures, triggering E:20b0. In conventional vented or condenser models sharing this code, the lint filter blockage is the more common culprit, as accumulated lint sharply reduces the air volume moving through the heater assembly.

Diagnosing this code starts with inspecting and cleaning the lint filter, which should be done after every cycle as a standard practice. If the filter is clean and the error persists, check the heat exchanger or condenser unit for lint buildup or ice accumulation. Ensure the dryer is installed in an environment where ambient temperatures are within the recommended operating range. Persistent faults after cleaning may indicate a failed temperature sensor, a defective evaporator, or a blocked exhaust duct requiring further inspection.