Feel the outside vent while the machine runs
Go outside, or to wherever the duct discharges, and hold a hand near it during a cycle. Strong warm air means heat and airflow are both present and the problem is elsewhere. Warm but weak air means a restriction. Cool air moving well means a heating problem. That one observation splits the whole diagnosis and needs no tools.
What you find
- The load is damp after a full cycle and the drum is hot — Heat without airflow, which is the restriction branch.
- The cycle runs unusually long before finishing — The machine extending itself trying to reach a dryness it cannot achieve.
- Clothes are hot to the touch but still wet — Classic restricted airflow: the moisture cannot leave the machine.
- The drum turns but never feels warm — The heating branch instead, which is a different set of causes.
- Lint appears around the door seal or behind the machine — Air escaping where it should not, which accompanies a restricted duct.
- NEAR MISS: one very heavy item still damp in an otherwise dry load — Normal, especially with towels or seams, rather than a fault.
Ranked for a damp load
- A restricted exhaust duct — First by a wide margin. Lint accumulates along the whole run, and a long or crushed duct chokes the airflow the machine depends on.
- A filter that looks clean but is not — Second. Fabric softener leaves an invisible film across the mesh that blocks air while letting light through.
- Overloading — Third. A drum packed tight cannot tumble, and clothes that do not tumble cannot present wet surfaces to moving air.
- A heating fault — Last for this complaint, and it is identified immediately by cool air at the vent.
Vent test, then the easy restrictions
- Feel the air at the outside vent during a cycle — It splits heat from airflow in one observation and costs nothing.
- Pull the filter and hold it under running water — The second cause, and the test is unambiguous: a filmed filter will not pass water freely.
- Check the duct behind the machine is not crushed or kinked — The top cause is often visible in the first stretch behind the appliance.
- Halve the load and run a shorter cycle — It clears the third cause and gives a clean comparison.
Owner steps
- Run a cycle and feel the air where the duct discharges outside — Strong and warm is healthy. Weak is a restriction. Cool is a heating problem.
About 15 min
- Take out the lint filter and run water onto the mesh — If water pools rather than passing straight through, softener film is blocking the air as well.
Tools: warm waterAbout 10 min
- Scrub the filter with a soft brush and a little detergent, then dry it — This restores an invisible restriction that a visual check cannot detect.
Tools: brushAbout 10 min
- Ease the machine out and check the duct is not crushed against the wall. Get a second person before you pull the cabinet out or tilt it. — A flattened first bend chokes the whole run, and it is the commonest single restriction.
Tools: flashlightAbout 20 min
- STOP before the duct is dismantled or any panel is opened — Mains voltage and a heater circuit sit behind the cabinet, and that is the boundary.
Before moving or opening
Safety
Unplug the appliance or switch off its breaker before removing any panel, and never run the machine with a panel off. Lint is combustible: a restricted duct on a heated machine is a fire risk, not merely an inconvenience. Leave the door switch wired exactly as the factory fitted it, and stop at once if you smell anything scorched.
When to call
Call for a duct cleaning if the vent airflow is weak after the filter and the first bend are clear, since most of the run is inaccessible. Call a technician instead if the air is cool and moving well, because that is a heating fault. Call immediately for any burning smell: a restricted duct on a hot machine is a genuine fire risk.
Nearest pages of this class
Scope
Written for the LG dryer class rather than one model line. Duct runs are a property of the installation rather than the appliance, and filter designs and cycle behaviour differ by family; the page for your specific machine is the more precise answer.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
