The short answer
A Bosch WTG-series dryer that tumbles without drying is usually short of airflow rather than short of heat, because a ventless condensing dryer depends on a loop that a restriction closes long before anything electrical fails. this designation denotes the element-heated condensing platform, and the tell is at the end of a cycle: the load comes out hot to the hand and the cycle is comparatively short. That distinction decides the whole check order below, and it is the reason a heat-pump machine that feels cool at the end of a cycle may be working perfectly.
What you observe
- The load is warm but never dries — Heat is present; the moisture has nowhere to go.
- Cycles have been creeping longer for weeks — A restriction building gradually rather than a part failing suddenly.
- The cabinet or the room gets noticeably hot — Heat being dumped where it should not be, which is an airflow story.
- The machine cuts out part way and restarts cold — Something has protected itself, and it protected itself for a reason.
- NEAR MISS - the load is dry but only lukewarm to the hand — On a heat-pump machine that is the design rather than a fault: it dries below the temperature an element works at, and a cool dry load is a working machine.
Likeliest causes here
- The lint filter blinded — Lint you can see is not the problem; the softener film you cannot see is, and it closes the mesh to air while looking clean. First, because on these models it is first because it is free, instant and right more often than anything else.
- A thermal cut-out that has opened — Restrict the air and the machine gets hot where it should not; the cut-out opens and the heat stops, which is the protection working. Second on these models: the construction here brings it forward from where a generic list would put it.
- The heat exchanger or condenser block packed — The second stage of the loop collects what gets past the filter, and a packed exchanger stops the machine condensing at all. Third on this family - an owner job behind the lower flap and the one most often skipped.
- The heating element or its relay — An element that has gone open circuit gives tumbling without heat and nothing else. It comes last here - straightforward to confirm with a meter and not an owner check.
- Where this ranking departs from the brand-generic page — The cause that moves is the lint filter blinded. It leads on this family because this panel is the only place the machine can be told anything. That is a property of the platform rather than of the brand, which is why the page above this one cannot rank it the same way.
Check in this order
- Run a hot tap through the lint filter — Water should pass straight through the mesh. Beading water is a blinded filter, and that alone stops a load drying. It leads on these models because the construction puts it within reach before anything else on the list.
- Note whether heat stops part way rather than never starting — Heat that dies mid-cycle is protection tripping, and the restriction that tripped it is the real fault.
- Open the lower flap and clean the exchanger properly — Follow the plate on the flap. This is the single highest-value check on this platform and it needs no tools.
- Note whether the drum ever gets warm at all — Tumbling with no warmth at any point, on a clean machine, points at the heat source.
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, and the heating side of a dryer holds more stored energy than most of the cabinet. Let it cool before opening the lower flap. Never bypass or bridge a thermal cut-out to get heat back: it opened because something restricted the air, and defeating it is how a restriction becomes a fire.
When to call
The filter, the exchanger behind the lower flap, the tank, the room and the load are owner ground on these models, and on this platform they explain most no-heat calls outright. The line is the heat source: a clean machine that still tumbles cold needs a meter, and that means the cabinet open.
Nearest pages
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
