Tumble dryer not heating: causes and safe checks

Likely needs an engineer

Quick answer

First rule out the simple causes: a full water tank, a blocked fluff filter or condenser, or a dryer shut in an unventilated space. Heat pump dryers can also seem cold at the start. Then run AEG’s heat test. If the drum is still cold, the heater has likely failed: Bosch says not to attempt that repair yourself.

Also covers: tumble dryer blowing cold air · tumble dryer not getting warm.

This can be normal

AEG says heat pump dryers dry at lower temperatures and can seem not to heat for a long time at the start of a cycle. That is normal.

Likely causes

Why this can need an engineer

The heater (or heat pump) and its safety thermostats are inside the dryer, behind panels. Bosch says not to attempt a heater repair yourself. Overheating dryers are a fire risk, so if it still isn’t heating after the checks, stop using it and book an engineer.

What you can safely check yourself

Stop and call a qualified engineer if:
  • It still doesn’t heat after the checks. Heating faults need an engineer.
  • You smell burning, see smoke or scorch marks, or the appliance trips your electrics. Stop using it, and switch it off at the wall only if it is safe to reach. Otherwise switch off at the consumer unit.
  • The next step would mean removing a cover or panel, or working on the pump, valves, heater, motor, door lock or wiring. That is a job for a qualified engineer.
  • The appliance is still under warranty. Contact the manufacturer first, because DIY work can affect your cover.

Work through these in order. Stop as soon as one of the signs above applies.

Empty the water tank and seat it properly

  1. Condenser and heat pump dryers only. Pull the water tank out slowly and keep it upright. The water may be warm.
  2. Empty it into a sink and push it fully back into place. A tank that isn’t seated properly won’t collect water.
  3. Empty it after every cycle, unless your dryer drains through a hose.

Clean the fluff (lint) filter

  1. Open the door and pull out the fluff filter. On most models it sits in the door opening.
  2. Open it and remove the fluff with your fingers. Use a vacuum cleaner for heavy build-up, and clear fluff from the filter slot and door seal too.
  3. Hold the filter up to the light. If you can’t see through it, residue is blocking it. Wash it under running water and let it dry.
  4. Refit it fully. Do this after every load.

Never run the dryer without the filter fitted.

Replace a torn filter rather than using it.

Clean the condenser or heat exchanger Take care

Before you start
  • Switch off and unplug the appliance at the wall socket before you touch hoses, filters or the back of the machine. Make sure your hands and the plug area are dry.
Tumble dryer filter, tank and condenser Water tank empty after every cycle Fluff filter in the door opening Condenser cover condenser/heat pump only
Tumble dryer filter, tank and condenser. Positions vary by model — check your manual.
  1. Condenser and heat pump dryers only. Open the condenser cover as your manual shows.
  2. Heat pump dryers: remove fluff from the heat exchanger with a damp cloth or a vacuum brush attachment. Wear gloves, because the metal fins are sharp, and don’t bend them.
  3. Condenser dryers: if your model has a removable condenser block, slide it out level so it doesn’t spill, rinse it through over a basin, and refit it.
  4. Close and lock the cover. Check the condenser at least once a month.

Don’t run the dryer with a condenser blocked by fluff.

Check the room temperature and ventilation

  1. Dryers work best in a ventilated room between about 5°C and 35°C.
  2. Don’t run a dryer shut inside an unventilated cupboard. Leave space around it.
  3. In a small room, open a door or window while it runs.

Test whether the dryer is heating

  1. Clean the fluff filter and condenser first.
  2. Run a long timed drying programme with no load. Stay nearby while it runs, and stop it straight away if you smell burning.
  3. After about an hour, with time still remaining, open the door and check whether the inside of the drum is warm.
  4. If it is still cold, the heating system may be faulty. Book an engineer.

Don’t leave the dryer running unattended during the test, or overnight.

Step-by-step guides

Related problems

More tumble dryer problems and codes, or use the fault finder.

Sources

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