The short answer
Two different faults look identical here: no heat at all, and heat that cannot get to the clothes. On a commercial-duty dryer running many more cycles a week than a household one, where wear parts and airflow are maintenance items rather than surprises, sort those apart first — it decides whether this is a lint job or a parts job.
What you are actually seeing
- The drum turns for a full cycle and the clothes are still damp — The machine is running, so this is heat or airflow rather than a mechanical failure.
- The load is hot but still wet — Heat is being made and moisture is not leaving. That is airflow, and the vent or condenser path is where to look.
- The load is cold and dry-ish after a long cycle — No heat at all, which on an electric machine can be as simple as half the supply missing at the breaker.
- Cycles have been getting longer for months — Gradual loss is the signature of lint accumulating, not of a component failing.
- The machine runs hot enough to smell and then stops heating — A protective cut-out doing its job. Stop and clear the airflow path before running it again.
- Not this fault: the drum does not turn at all — That is a no-start or a drive fault, and it belongs on the page for a dryer that will not start.
Causes, most likely first on this machine
- A restricted vent or a clogged lint filter — First on every platform, and by a distance: a crushed flexible duct, a long run with too many bends, a blocked outside flap or a filter that lint passes around rather than through. It is also the cause that creates several of the causes below.
- A thermal cut-out or thermal fuse opened by that restriction — Second: the fuse or cut-out is a safety device that has done exactly what it was fitted to do. Replacing it without clearing the airflow only means fitting another one shortly afterwards.
- Overloading, or a load that was too wet to begin with — Third, and free to test: a drum packed past the point where clothes can tumble dries nothing evenly, and a load that came out of a washer with a failed spin arrives carrying far more water than the machine is sized to remove.
- The heating element, igniter, flame sensor or gas valve coils — Fourth: an element open on an electric machine, or an igniter or coil failure on a gas one. Both are real, both are diagnosed with a meter, and both are far less common than lint.
- Half the electrical supply lost at the breaker or outlet — Fifth, and worth knowing about: an electric dryer whose supply has lost one leg will tumble perfectly and never warm up. It looks like an expensive fault and it is often a breaker.
- A cycling or operating thermostat that has drifted — Last: it produces weak heat rather than no heat, and it is worth reaching only once airflow and supply have been proven.
Check in this order, and why
- Clean the lint filter and look at the housing beneath it — Free, immediate, and it is the single most productive minute you will spend on this fault.
- Check the vent along its whole length — Including the outside flap, which is where lint and nesting birds collect out of sight.
- Run a short cycle and feel the exhaust — Strong warm flow means airflow is fine and the fault is elsewhere; weak flow names the cause without opening anything.
- Check the breaker properly on an electric machine — A dryer can tumble on half its supply, so a breaker that looks on is not proof that both legs are live.
- Only then suspect elements, igniters, coils or thermostats — Everything from here needs a meter, and on a gas machine it needs someone qualified to work on the gas train.
What an owner can safely check
- Clean the lint filter and wash it if it is glazed — Fabric-softener residue forms a film that passes light but not air. Warm soapy water and a brush, then dry it fully before refitting.
Tools: warm water, soft brushAbout 15 min
- Clear the lint housing under the filter — Unplug first. A narrow vacuum nozzle into the housing removes what the filter never caught.
Tools: vacuum, narrow nozzleAbout 20 min
- Disconnect and clear the duct, then check the outside flap opens — Pull the duct off, clear it by hand and by vacuum, and confirm the flap outside lifts freely when the machine runs.
Tools: vacuum, screwdriverAbout 40 min
- Run a timed cycle with a small load and compare — A single towel dried on a short cycle tells you more about the change you just made than a full load does.
About 30 min
- Stop here if the next step is a meter on the element, the igniter or the gas train — Those sit at line potential, and on a gas machine the valve train is not owner work at all.
Before you open anything
Safety
Unplug the appliance or switch off its breaker before removing any panel — a capacitor can hold a charge after the power is off. Lint is fuel: a dryer running against a blocked vent is the classic appliance fire, so clear the path before running the machine again rather than after. If you smell gas: do not switch anything on or off, leave the building, and call the gas utility or the emergency services from outside — do not look for the leak yourself. Never run the machine with its rear or top panel off, and never replace a thermal fuse without finding what opened it.
When to call a technician
Call once the airflow path is genuinely clear and the machine still will not heat, because everything past that point means a meter on live terminals or work on a gas valve train. Call straight away for any burning smell that survives a filter clean, for scorch marks around the vent or the plug, or for a gas machine whose burner lights and goes out repeatedly. On an electric machine, ask the technician to confirm both legs of the supply before any part is fitted — it is the check that most often turns an expensive quote into a breaker reset.
Sources
Documented- 29 CFR 1910.147 — The control of hazardous energy (lockout/tagout) — osha.gov, fetched 2026-09-12
- U.S. Consumer Product Safety Commission — product safety and recall notices — cpsc.gov, fetched 2026-09-12
Nearest pages of this class
What this page does not cover
This page is written for the appliance class under this nameplate rather than one family or model. Element ratings, thermostat trip points, igniter types, duct specifications and part numbers differ by platform and belong on the model-specific page linked below where one exists. Gas supply work and duct installation to code are outside it entirely.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
