Cover graphic by KnackDaily.
A restricted vent is the most common reason a dryer stops producing heat, and it is also the reason dryers start fires. Lint builds up in the duct, airflow drops, heat backs up inside the cabinet, and a safety device shuts the heating element down. Clear the duct before you suspect any part.
The vent comes first because it is a fire hazard
Lint is fine, dry, and extremely flammable, and the duct behind a dryer collects it steadily no matter how faithfully you empty the lint screen. A packed duct does two things at once. It traps heat inside the machine, which is what trips the safety cutoff and leaves you with a cold tumble. And it puts that heat next to an accumulation of the most ignitable material in your laundry room.
Pull the dryer out, disconnect the duct, and look. Flexible foil and plastic ducting sags and crushes behind the machine and should be replaced with rigid or semi rigid metal. Clear the full run out to the exterior hood, not just the first arm’s length, and check that the outside flap opens freely and is not blocked by a bird nest or paint.
Causes in order, and which ones need the power off
- Blocked vent or crushed duct. Safe to inspect. Do this before anything else.
- Overloaded drum or a wet heavy load. Free to test. Run a small load and compare.
- Wrong cycle selected. Air fluff and delicate settings run cool on purpose.
- Half the electrical supply lost. Reset the double breaker fully off then on. If it trips again, stop and call an electrician.
- Blown thermal fuse. Power off at the breaker and unplugged before the panel comes off. Almost always caused by the airflow problem above.
- Failed heating element or gas igniter. Power off, and for gas models the supply valve closed. This is where most people should hand it over.
Anything past the first three steps means working inside a cabinet that carries high voltage or gas. Unplug the machine or switch off its breaker before any panel comes off, and if that sentence makes you uneasy, that is a reasonable signal to call someone.
Match what the machine is doing
| What happens | Where to look |
|---|---|
| Tumbles normally, no heat at all | Electrical supply, thermal fuse, or heating element |
| Warm but clothes still damp after a cycle | Airflow restriction in the duct |
| Very hot outside, long cycles | Heat is not escaping. Vent again. |
| Heats for a while then goes cold | A cycling thermostat or a limit switch opening |
| Nothing runs at all | Door switch, outlet, or breaker |
| Burning smell during operation | Stop the machine, unplug it, inspect for lint |
Gas and electric dryers fail in different places
Electric models heat with a resistive element fed by a circuit made of two live legs. Lose one leg and the drum still spins while the element sits dead, which is why a partial breaker trip produces the classic no heat complaint. Gas models heat with a burner that depends on an igniter, a flame sensor, and gas valve coils, so their failures announce themselves as a burner that clicks and never lights. If you smell gas at any point, leave the house and call the utility from outside.
When to stop and call a technician
Call for service if the breaker trips again after a reset, if you smell gas or burning, if the machine has scorch marks inside the cabinet, or if the thermal fuse has blown more than once. That last one in particular says the airflow problem is still there. Replacing a safety cutoff without solving what tripped it is the change that turns an inconvenience into a fire.
