Two complaints arrive under the same words and they are not the same fault:
- "It runs but there is no heat at all." The drum turns, the cycle completes, the clothes come out cold and soaking. This is an electrical or gas fault.
- "It gets hot but the clothes are still damp after a full cycle." This is almost always airflow, and I have written separately about what Boston's triple-decker duct runs do to it.
This piece is about the first one.
Check these before anything else
Electric dryers run on 240 volts through two legs. That is enough to kill, and the terminal block stays live even when the drum is dead, so everything below the breaker check is work for someone with a meter who knows how to prove the circuit dead before touching it. If one leg is lost — a tripped half of a double-pole breaker, a failed breaker, a loose neutral — the motor still turns on 120 volts and the heating element gets nothing. So: a dryer that tumbles perfectly with no heat whatsoever is very often a breaker problem, not a dryer problem. Switch the breaker fully off, then on. If your dryer is on two separate single-pole breakers rather than a double-pole, check both.
Gas dryers: confirm the gas is actually on. If you have a gas range and it lights, the meter is on, but the dryer has its own shutoff valve behind or beside the machine and it does get closed during moves and boiler work.
Check the cycle you selected. Air fluff, air dry and refresh settings deliberately run with no heat. This is an embarrassing number of calls.
Electric dryer, still no heat
The parts, in the order they fail:
| Part | What it does | Note |
|---|
| Thermal fuse | One-shot safety, blows on over-temperature | Almost always blows because of a blocked vent |
| Heating element | Coil that makes the heat | Fails open, sometimes visibly broken |
| Cycling thermostat | Controls normal operating temperature | Fails open, no heat |
| High-limit thermostat | Second safety | Same story as the fuse |
| Timer / control board | Sends power to the element circuit | Least common |
The thermal fuse deserves its own paragraph, because it is the most-replaced part on this list and the most-misunderstood. It is a safety device that blows when the exhaust gets too hot, and the exhaust gets too hot when air cannot leave. If a technician replaces your thermal fuse and does not check the vent, you will be back in a few months. That is not a coincidence and it is not a bad part. Ask what the airflow measured.
Gas dryer, still no heat
Gas machines add an ignition sequence, and the diagnosis is largely listening to it:
- Motor runs, blower spins.
- The igniter glows — you can see it through a vent slot in some machines.
- The gas valve coils open, the burner lights with a soft whoomph.
- Flame sensor confirms, igniter goes out, the burner cycles on and off through the cycle.
Where it stops tells you the part. Igniter glows and then fades with no flame: valve coils. Igniter never glows: igniter, or the flame sensor stuck closed telling the board there is already a flame. Lights and goes out immediately, repeatedly: often airflow again, tripping a limit.
Gas work is where I will ask you not to keep going on your own. Not out of trade protectionism: an unseated gas valve or a disturbed union leaks a fuel that pools and ignites, and a cracked heat exchanger vents carbon monoxide into a laundry room people sleep above. Diagnosing it properly needs a manometer, a combustible-gas detector and a licensed gas fitter — in Massachusetts that licence is a legal requirement for the work, not a credential we invented. Listening to the sequence, as described above, is safe. Opening the valve train is not. The rest of this you can safely investigate.
The test that separates the two complaints
Disconnect the exhaust duct at the back of the machine and run a timed heat cycle for two or three minutes with a damp towel in it. You now have a dryer with a perfect vent.
- Gets hot and dries the towel → the machine is fine. Your problem is the duct.
- Still no heat → the fault is in the machine, and the list above applies.
That single test decides which article you need and which technician's time you are buying.
What we bring
If you tell us "no heat at all, breaker checked, electric," we will arrive with an element, a fuse and a thermostat set for your model and it is usually a one-visit job. If you tell us "gets hot, still damp," we bring the airflow meter and a duct brush and we will very likely not sell you a part at all.
The model number, from the sticker inside the door frame or on the back panel, is what makes that possible.
