Dryer Duct Disconnected Inside the Wall — How to Find and Fix It
Diagnostic Checklist
Check the lint trap
Clean if not already done. A clogged lint trap restricts airflow before air even reaches the duct.
Inspect the flex transition behind the dryer
Pull the dryer forward and check that the flex transition is not kinked, crushed against the wall, or disconnected. Straighten or replace if needed.
Check the exterior cap from outside
Run the dryer and go outside. The cap should be open and you should feel strong warm airflow. A cap that barely opens or is covered in lint needs cleaning or replacement.
Clean the full duct run
If the above steps don't resolve the problem, a full DIY cleaning or professional service is the next step.
Check the duct length
If the run is over 35 equivalent feet, that's a structural problem — use the calculator to confirm and see Long-Run Solutions.
FAQ
DIY is fine for basic diagnosis and cleaning of accessible runs. Call a professional if: the duct is over 25 feet, there are multiple bends, the duct has never been cleaned, or you suspect a disconnection inside a wall. A pro has rotary brush equipment and a camera to inspect the full run.
Yes — heating element failure, thermostat failure, and motor issues can all cause symptoms similar to vent restriction. If cleaning and inspection confirm the vent is clear and the cap is operating correctly, the dryer itself may need service. The key diagnostic test: if the dryer exhausts weak airflow even with the transition duct disconnected, the problem is in the dryer, not the vent.