When a dryer tumbles normally but produces no heat, three components account for nearly every case. On electric dryers the heating element itself can burn through, and the thermal fuse, a one-time safety device, can open. On gas dryers the hot surface igniter weakens until it no longer gets hot enough to open the gas valve, or one of the gas valve coils fails. There is an important asymmetry here. The heating element and the igniter are wear items that fail on their own schedule. The thermal fuse is not: it is a safety device designed to open when the dryer overheats, and it overheats because air cannot leave the drum.
That is why replacing a thermal fuse without finding out why it blew is the most common mistake in dryer repair. The new fuse will open again, usually within weeks.
The Diagnostic Order That Matters
| Step | Check | What it tells you | Cost if this is it |
|---|---|---|---|
| 1 | Vent and lint path airflow | The root cause behind most no-heat faults | $0 – $250 vent cleaning |
| 2 | Thermal fuse continuity | Open fuse confirms a prior overheat event | $180 – $280 |
| 3 | Cycling thermostat and thermistor | A stuck thermostat causes overheating | $190 – $320 |
| 4 | Heating element resistance (electric) | Open element reads infinite; healthy reads 8 to 15 ohms | $220 – $380 |
| 5 | Igniter glow and current draw (gas) | Weak igniter never opens the valve | $220 – $360 |
| 6 | Gas valve coil resistance (gas) | Coil fails open; igniter glows then nothing | $240 – $420 |
| 7 | High-limit thermostat | Secondary safety; opens on severe overheat | $190 – $330 |
| 8 | 240V supply, both legs (electric) | One dead leg means the drum turns but no heat | Electrician, not us |
Step eight is worth knowing about. An electric dryer runs on two 120V legs. If one leg is lost, through a half-tripped breaker or a failed breaker pole, the motor still runs on the surviving leg while the element gets nothing. The dryer looks like it has a heating fault but the problem is in the panel.
Why the Thermal Fuse Is a Symptom, Not a Cause
A thermal fuse is a sacrificial link that melts at a set temperature, typically around 200°F to 350°F depending on location. It exists because a dryer that cannot exhaust its hot air becomes a fire risk, and clothes dryers are a leading cause of home appliance fires in the United States, with failure to clean the lint path the leading contributing factor.
So an open thermal fuse is the safety system reporting that the dryer overheated. The three things that cause that overheat:
- A restricted vent. Lint in the duct, a crushed flexible hose, a long run with several elbows, or a blocked exterior flap. By far the most common.
- A clogged lint screen or blower housing. Lint bypassing a damaged screen packs the blower wheel.
- A failed cycling thermostat stuck closed, so the element never shuts off during the cycle.
Fitting a fuse without addressing these is not a repair. The full airflow picture is on why does my dryer take so long to dry.
Electric and Gas Dryers Fail Differently
Electric dryers. The heating element is a coiled resistance wire in a housing. It burns through at a point and the circuit opens, which is easy to confirm with a meter and often visible on inspection. Element plus thermal fuse is the usual repair, at $220 to $380.
Gas dryers. The sequence is: the igniter glows, the flame sensor confirms it is hot enough, the gas valve coils open, gas ignites. A failure anywhere in that chain gives no heat. The classic pattern is an igniter that glows but no flame follows, which points at the valve coils rather than the igniter.
Gas work here is not optional DIY. In Massachusetts, work on a gas dryer valve, igniter, or supply connection requires a licensed gas fitter. We handle that through licensed gas dryer repair.
What to Check Before Calling
Three checks, with the dryer unplugged or its breaker off:
- Pull the lint screen and look down the housing. If you see packed lint below the screen, that is airflow restriction and it may be your whole problem.
- Disconnect the vent hose at the back and run the dryer briefly on a heat cycle. If it heats normally venting into the room, the fault is the duct, not the dryer. Do not run it that way beyond a short test.
- Check the breaker, on electric models. Switch it fully off and on again, because a partially tripped double-pole breaker is a real and commonly missed cause.
If none of that resolves it, book through washer and dryer repair. Component pricing is on the Boston pricing guide, and what is safe to tackle yourself is on can you repair a dryer yourself.