If the drum turns but the air stays cold, the motor circuit is fine and the heating circuit is not. On electric dryers the usual suspects are a restricted vent, a blown thermal fuse, a failed heating element or a lost leg of the 240 V supply. On gas dryers it is normally the igniter. Start with the vent — it is free to check and it is the root cause behind a surprising number of “failed” parts.
Why the vent matters most
Dryers are designed to move a steady volume of air through the drum. When the vent is clogged with lint, that airflow drops, heat builds up in the cabinet, and the safety devices do exactly what they are designed to do — cut the heat.
This matters for two reasons. First, a blocked vent is the most common underlying cause of a no-heat fault. Second, if you replace a blown thermal fuse without clearing the vent, the new fuse will blow too. Restricted dryer venting is also a well-documented fire risk, so it is worth doing properly.
Unplug the dryer, or switch off its breaker, before removing any panel. Electric dryers run on a 240 V supply and hold enough energy to be dangerous. For gas dryers, also close the gas shut-off valve before working on the machine.
Electric dryers: common causes
| Cause | How likely | Typical sign |
|---|---|---|
| Blocked or crushed vent duct | Very common | Long dry times before the fault; very hot cabinet |
| Blown thermal fuse | Very common | Dryer runs, no heat at all, often after a blocked vent |
| Failed heating element | Common | No heat; element coil visibly broken when inspected |
| Tripped or failed thermostat / thermal cut-out | Common | Intermittent heat, or heat that stops mid-cycle |
| One leg of the 240 V supply lost | Occasional | Drum turns normally but never heats — half the breaker tripped |
| Failed timer or control board | Uncommon | Everything tests good but no heat is commanded |
Gas dryers: common causes
| Cause | How likely | Typical sign |
|---|---|---|
| Failed igniter | Very common | Igniter does not glow; no ignition sound |
| Faulty gas valve coils | Common | Igniter glows then goes out with no flame |
| Failed flame sensor | Common | Brief flame that dies immediately |
| Gas supply turned off | Occasional | Other gas appliances also affected |
| Blocked vent | Very common | Same airflow issue as electric models |
How to diagnose it
- Clean the lint filter, then the vent
Take the filter out and wash it — a film of fabric softener residue can block airflow while still looking clean. Then disconnect the duct from the back of the dryer and clear it end to end with a vent brush. Check the outside flap opens freely and is not blocked by lint, a bird’s nest or debris.
- Run the dryer with the duct disconnected
With the duct off, run a short heated cycle and feel the exhaust air at the back. If it now heats properly, the vent was the problem and there may be nothing else wrong.
- Check the breaker properly
On an electric dryer, one half of a double-pole breaker can trip while the other stays on. The result is a drum that turns with no heat. Switch the breaker fully off and back on rather than just looking at it.
- Test the thermal fuse
With the machine unplugged and the back panel off, find the thermal fuse on the blower housing or exhaust duct. Test it for continuity with a multimeter. No continuity means it has blown — but treat that as a symptom, and clear the vent before fitting a new one.
- Inspect the heating element
Look through the element housing for a visibly broken coil, and test the element for continuity. A break in the coil means the element needs replacing.
- Watch the igniter on a gas dryer
With the lower panel off, start a cycle and watch. The igniter should glow bright orange, then the gas valve should open and the flame light. Which stage it fails at tells you whether the igniter, the coils or the flame sensor is at fault.
Jumping out a thermal fuse to “test” a dryer removes the only protection against a runaway heating element in a lint-filled cabinet. If a fuse has blown, find out why.
When to call a professional
Gas dryers should be worked on by a qualified gas engineer beyond checking the vent and observing the ignition sequence — gas valves, burner assemblies and flue connections are not DIY territory. On electric dryers, call an electrician if a breaker keeps tripping, or if you find scorched wiring or damaged terminal blocks.
Stop and call a qualified appliance technician or electrician if you find scorched or melted wiring, smell burning, see water that has reached electrical components, or if the fault returns immediately after a repair. Never bypass a safety device — thermal fuses, door interlocks and flood switches fail for a reason, and defeating one converts a broken appliance into a fire or flood risk.
