Summary

"Not spinning" is a different fault family from "not heating," and the two get confused constantly by customers and sometimes by inexperienced engineers. A dryer that tumbles fine but blows cold air is an airflow, element, or thermostat fault — covered separately in tumble dryer not heating. A dryer where the drum simply doesn't rotate — clothes sitting motionless while the machine runs, or the machine not starting the cycle at all — is a mechanical or electrical drive-chain fault, and this guide covers that fault family specifically, across vented, condenser, and heat pump dryer types.

The drive chain in a domestic tumble dryer is mechanically simple compared to a washing machine: a single motor drives the drum via a belt (on most vented and condenser models) or, on some heat pump and premium models, a direct-drive or gearbox arrangement. That simplicity means the fault list is short and usually easy to diagnose with a multimeter, a torch, and the back or front panel off — but it also means a stalled motor under load can trip a thermal cut-out or burn out carbon brushes within minutes if the underlying jam (a foreign object, a collapsed bearing) isn't found and cleared first.

This guide takes you through listening-based triage, the specific tests for each of the five common causes, and where the fault sits differently between vented, condenser, and heat pump dryer designs. It assumes domestic single-phase 230V appliances; commercial/launderette dryers have different drive and safety-interlock designs not covered here.

Key Facts

Quick Reference Table

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Symptom Sound Likely cause Typical fix
Nothing happens when started Silent Door interlock not registering closed, blown fuse, dead PCB Check door catch alignment/microswitch continuity, check plug fuse, check PCB power
Motor hums, drum doesn't turn Humming/buzzing Snapped or slipped belt, seized bearing, failed start capacitor Inspect belt, test bearings by hand-turning drum, test capacitor
Drum turns freely by hand but motor won't drive it Silent or clicking Belt off the pulley, belt snapped Refit or replace belt
Grinding or thudding before stopping Loud grinding Foreign object jam, or bearing collapse Remove drum, clear object, inspect/replace bearings
Runs briefly then stops, won't restart for a while Runs then silent Motor thermal cut-out tripped from overheating Let motor cool, find and fix root cause (jam/bearing) before restarting
Intermittent stalling under load, especially when full Struggling/slowing hum Worn carbon brushes Test brush length, replace brush set
Works with door held shut, not with door closed normally Silent when released Door catch misaligned or switch worn Adjust or replace door catch/microswitch
Heat pump/direct-drive model — total silence, no hum at all Silent Motor or gearbox failure, or PCB fault Test motor windings, check PCB output to motor circuit

Detailed Guidance

Triage by sound — the fastest first diagnostic

Dryer won't spin
      |
      v
Press start — what do you hear?
      |
      +-- Nothing at all (totally silent) -------> Door interlock / fuse / PCB branch
      |
      +-- A hum or buzz, but drum stays still ----> Belt / bearing / capacitor branch
      |
      +-- Runs briefly, then cuts out -------------> Thermal cut-out branch
      |
      +-- Grinding/thudding, then stops -----------> Foreign object / bearing collapse branch

Door interlock / fuse / PCB branch

  1. Check the door is latching fully. Open and close it firmly — listen and feel for a positive click. A worn catch or a door hinge that's dropped slightly can leave the door looking shut while the microswitch isn't fully depressed.
  2. Test the door microswitch with a multimeter (mains isolated) — continuity should change cleanly as the door catch operates it. A switch that's intermittent or doesn't register at all needs replacing; these are inexpensive, commonly-stocked parts across most brands.
  3. Check the plug/appliance fuse and any dedicated circuit protection. A blown fuse with no other symptoms is uncommon but quick to rule out.
  4. Check for power reaching the PCB. If the interlock and fuse test fine but there's still no response at all, the control board itself may have failed — test with a multimeter for supply voltage at the board's input terminals; a board with power in but no output to the motor circuit needs specialist diagnosis or replacement.

Belt / bearing / capacitor branch (motor hums, drum doesn't turn)

  1. Isolate from the mains before opening any panel.
  2. Access the drum — on most vented/condenser dryers this means removing the front or top panel per the model's service layout; heat pump models may require removing the heat exchanger unit first.
  3. Try turning the drum by hand. If it turns freely and easily, the belt has likely snapped or come off the pulley — inspect visually. If it's stiff, gritty, or won't turn at all, suspect a seized bearing or a foreign object jam before assuming it's the belt.
  4. Inspect the belt for cracking, glazing (shiny, hardened rubber), or a clean snap. A belt that's simply slipped off the motor pulley (rather than broken) can sometimes be refitted, but check for the underlying cause — a belt doesn't usually jump off cleanly without a reason (worn idler pulley, bearing dragging).
  5. Test a start/run capacitor if fitted — a failed capacitor causes the motor to hum on power-up but never build enough torque to overcome starting resistance. A capacitor tester or an appropriately rated multimeter capacitance function will confirm; replace like-for-like on rating.
  6. Check drum support rollers/bearings by feeling for play or grinding as you rotate the drum by hand with the belt removed. Felt-lined or plastic rollers wear and eventually seize or split; on some designs the rear bearing is a sealed unit pressed into the back panel — replacement scope and cost varies significantly by design, so confirm parts availability before quoting.

Thermal cut-out branch (runs briefly, then stops)

The motor's thermal cut-out is a protective device, not the root fault — it trips because the motor is working harder than it should, almost always because something downstream (a jam, a seized bearing, an overloaded drum) is resisting rotation. Letting the motor cool and simply restarting without finding the underlying cause risks repeating the trip, or in a worst case, burning out the motor windings.

  1. Allow the motor to cool fully (can take 30–60 minutes) before further testing.
  2. While it's cooling, investigate the mechanical side — drum bearings, belt tension, any foreign object — using the belt/bearing branch above.
  3. Once cooled, test the motor windings for continuity and check the thermal cut-out itself hasn't failed open permanently (some are one-shot and need replacing, others self-reset).
  4. Only restart the appliance once you've found and fixed the mechanical cause, or you're confident there isn't one (e.g. the customer had genuinely overloaded the drum on a one-off occasion).

Foreign object / bearing collapse branch

A grinding, thudding, or knocking noise immediately before the drum stops turning is a strong signal of either a trapped foreign object between the drum and the outer drum casing, or a collapsed bearing that's let the drum drop out of true alignment. Both require the drum to be removed for inspection — do not attempt to keep running the appliance to "see if it clears," as this risks damaging the drum surface, the heating element, or the motor.

  1. Remove the drum per the model's service sequence (varies significantly between brands and vented/condenser/heat pump types).
  2. Inspect the drum interior, the gap between drum and outer casing, and the rear/front bearing housings for debris.
  3. If bearings are worn, replace as a set rather than individually where the design uses a shared support assembly — mixing old and new bearings on the same drum is a common cause of early repeat failure.
  4. Reassemble, refit the belt with correct tension per the service manual routing diagram, and test run empty before returning the load.

Direct-drive and heat pump model differences

Increasingly, heat pump dryers and some premium models use a direct-drive or gearbox motor arrangement with no belt at all. On these designs, a stalled drum with the motor audibly trying to run points more directly at the motor itself, a gearbox fault, or the control electronics, rather than a belt — there is no belt to inspect. Access is also often more involved, since the heat exchanger and heat pump unit typically needs to be removed or partially disassembled before the drum drive is reachable. Confirm the specific service access sequence for the model before quoting labour time, as this varies more between manufacturers on heat pump models than on the broadly standardised vented/condenser belt-drive layout.

Right to repair — spare parts availability

Since UK regulations implementing "right to repair" requirements for certain domestic appliances came into force, manufacturers of covered product categories are required to make specified spare parts available to professional repairers for a set number of years after a model goes off sale.. In practice, this means belts, drums, and common electrical/mechanical wear parts are increasingly available well beyond the point older dryers would have become unrepairable — always check current part availability before advising a customer to scrap rather than repair.

Frequently Asked Questions

The dryer hums but the drum doesn't move — is it definitely the belt?

Not necessarily. A humming motor with a stationary drum can mean the belt has snapped or slipped, a bearing has seized so hard the belt can't turn the drum, or a start capacitor has failed so the motor can't build starting torque. Try turning the drum by hand with the machine isolated — if it's stiff or won't move, suspect the bearings before the belt.

Why did the belt snap with no warning?

Rubber drive belts degrade gradually through repeated heat cycling over years, but the actual snap is often sudden because the belt has been running increasingly glazed and brittle for some time before final failure. A belt snapping shortly after a service visit that didn't flag it isn't necessarily a missed diagnosis — belts can look intact right up to the point of failure. It's worth proactively mentioning belt condition and age to customers during any dryer service call.

Is it worth repairing a tumble dryer that's stopped spinning, or should the customer replace it?

Depends on the fault and the machine's age. A belt or door switch replacement is a low-cost, quick repair worth doing on almost any machine. A bearing/drum replacement on an older, lower-value machine may approach or exceed the cost of a new budget dryer — quote both options and let the customer decide, similar to the repair-vs-replace logic used for boilers. Motor or PCB failure on a machine over 8–10 years old is usually the point where replacement becomes the more sensible advice.

Can a blocked vent or lint filter cause the drum to stop spinning?

Not directly — a blocked vent or clogged lint filter causes airflow and heating faults (covered in tumble dryer not heating), and on some models with a safety thermal cut-out on the heater circuit, severe overheating from a fully blocked vent could in rare cases also trip a thermal protection device that stops the whole cycle. But a genuinely stationary drum with the motor otherwise trying to run is a mechanical drive-chain fault, not an airflow fault — don't spend time on vent clearance if the drum itself won't turn by hand.

Do I need any special certification to repair a tumble dryer?

No trade-specific statutory registration equivalent to Gas Safe or NICEIC applies to appliance repair itself, but general electrical safety competence applies to any work involving mains wiring, and PAT testing standards (BS EN 60335 household appliance safety) are relevant if you're also testing the appliance's electrical safety as part of the job. Always isolate from the mains before opening any panel.

Regulations & Standards