When a dryer starts needing two or three cycles to fully dry a normal load, it’s easy to assume the machine is just getting old. In most cases, it’s actually a specific, fixable restriction — and one that’s worth taking seriously.
Airflow Restriction Is the #1 Cause
A blocked lint screen or a clogged, crushed, or overly long exhaust vent is by far the most common reason drying performance drops off, and it’s exactly what triggers the E12 error code on Bosch dryers. This isn’t just a performance issue — restricted airflow is one of the leading causes of dryer fires nationally.
What You Can Check Safely
Clean the lint screen thoroughly before every load, and check that the exterior vent flap opens freely and isn’t blocked by debris, snow, or a bird’s nest. If your vent run is long or has multiple bends, buildup can accumulate well before it’s visible from either end.
When It’s a Sensor, Not Airflow
If airflow checks out clear and drying is still inconsistent, the NTC temperature sensor that regulates heat may be failing, which shows as an E52 error code.
Don’t Wait on This One
Because of the fire-risk factor, we recommend booking a dryer inspection promptly rather than living with multiple-cycle drying for months.
Not Confident Doing This Yourself?
A factory-trained technician can diagnose and fix it safely, usually same-day.