Start with the vent. A clogged dryer vent restricts airflow, the dryer overheats internally, and the thermal fuse trips as designed to prevent a fire. The thermal fuse is a one-shot device that has to be replaced. Replacing it without clearing the vent guarantees you'll be replacing it again. So the first useful action is to inspect the vent path, even before the fuse, because the fuse is almost always a symptom of the vent problem.
Quick checks
- Gas or electric dryer?
- When was the dryer vent last cleaned?
- Have any other gas appliances been working normally (gas dryers only)?
- Has the dryer been moved, pushed back hard, or had work done recently?
- Has the breaker been checked in the panel?
- Has the cycle selector been bumped to "Air Fluff" or "Air Only" by mistake?
Step by step
- Confirm the cycle is set to a heated cycle. "Air Fluff" and "Air Only" tumble without heat on purpose.
- Pull the dryer out and check the vent. Look at the transition duct behind the dryer and the path to the outside vent. Clear lint with a vacuum or vent brush. See dryer vent cleaning.
- Outside, check the vent hood. The flap should open with airflow when the dryer is running. A stuck flap or a pest screen packed with lint stops airflow.
- Check the breaker on electric dryers. Electric dryers use a 30A double-pole breaker. If one of the two legs has tripped or there's a loose neutral, the motor (which uses one 120V leg) runs but the heating element (which needs both legs for 240V) won't.
- Check the gas valve on gas dryers. The shutoff valve on the gas line behind the dryer should be parallel with the pipe (open). If perpendicular (closed), the dryer drum will still turn but no gas reaches the burner.
- If the vent is clear, gas is on, and breaker is fine but still no heat: internal parts (thermal fuse, heating element, gas valve coils, high-limit thermostat) need an appliance tech.
If the issue is a clogged vent
This is the most common cause. The dryer protects itself with a thermal fuse that opens (blows) when internal temperature exceeds safe limits. Lint accumulation in the vent traps hot, damp air; the heater compartment overheats; the fuse blows. After clearing the vent, the thermal fuse still needs to be replaced (it's one-time use). This is appliance technician work for gas dryers. For electric dryers, replacement is a common DIY task but involves removing the back panel and identifying the right fuse on the blower housing.
If a tech has replaced your thermal fuse before and it blew again, the vent is the answer.
If the issue is the gas valve (gas dryers)
The shutoff valve behind the dryer can get bumped during cleaning or moving. If it's closed, the dryer runs but doesn't heat. Turn it parallel to the pipe to open. Always run the dryer on a normal heated cycle for a few minutes after a power-off period to confirm gas is reaching the burner.
If the gas valve is open but the burner isn't lighting, the gas valve solenoid coils, ignitor, or flame sensor inside the dryer have probably failed. These are appliance-tech repairs on a gas appliance; don't open the burner compartment yourself.
If the issue is the electric breaker
An electric dryer needs 240V (two 120V legs) for the heating element. The motor only needs one 120V leg, so a tripped or failed half-breaker leaves you with a tumbling drum and no heat. Flip the double-pole breaker fully off and then back on. If it trips again, stop and call an electrician. A repeatedly tripping breaker means a short or failed element drawing too much current.
If the heating element has failed (electric)
The heating element is a coil inside a housing behind the drum. It can break with age, with vibration, or with overheating. When it breaks, the dryer tumbles normally and the controls work, but there's no heat. Replacement is a common DIY repair but requires removing the back panel and disconnecting the wires. If you aren't sure, an appliance tech can confirm with a meter and swap it in under an hour.
What not to do
- Don't keep running the dryer if you think a thermal fuse blew. The fuse blew for a reason and the underlying overheating problem usually hasn't been fixed yet.
- Don't open the burner compartment of a gas dryer. Combustion, gas, and electrical risk in one spot.
- Don't bypass a thermal fuse. It exists to prevent a fire and is required by code.
- Don't ignore a tripped breaker. Repeatedly resetting a tripped breaker can damage the electrical system or start a fire.
When to call for service
- Gas dryer with any heating issue, unless it's the shutoff valve.
- Electric dryer where the breaker keeps tripping.
- Replacement of the thermal fuse, heating element, or gas valve solenoids on most models.
- Burning smell, scorched plastic, or any sign of overheating beyond the heat coming from the element.
- Any electrical sparking or smoke.
Good maintenance rhythm
- Every load: clean the lint screen.
- Yearly: clean the full dryer vent path (transition hose, in-wall duct, exterior vent hood).
- Yearly: check the exterior vent hood for trapped lint, pest nests, and that the flap moves freely.
- Every 6 to 12 months: pull the dryer out and vacuum behind it and under it.
- After any "no heat" episode: clear the vent before paying for a thermal fuse replacement.
- Ongoing: don't dry rubber-backed mats, foam, or large quantities of fleece without checking the manual. They restrict airflow and load the lint screen unusually fast.