Tumble Dryer Not Heating: Fault-Finding Guide

Summary

A tumble dryer that spins but produces no heat is one of the most common domestic appliance callouts, and — unlike many appliance faults — it carries a genuine safety dimension that a washing machine or dishwasher fault doesn't: tumble dryer fires caused by lint accumulation near the heating element are a well-documented UK fire risk, and Whirlpool ran a large-scale safety modification programme and subsequent recall in the 2010s covering millions of affected machines sold under multiple UK brand names it owned. Every "not heating" diagnosis should start with airflow, both because it's the most common cause and because a blocked vent or filter is itself the precursor to overheating and fire, not just a nuisance fault.

The heating circuit in a tumble dryer is protected by multiple safety devices in series — a thermal fuse (usually one-shot, non-resettable) and a resettable thermostat/thermal cut-out (TCO) — that will cut power to the element the moment airflow across it drops too low or temperature rises too high. This means a genuinely healthy element can appear "dead" simply because a safety device upstream of it has correctly done its job. Diagnosing "no heat" therefore means working backward from the safety devices to the element, not assuming the element itself has failed.

This article covers the diagnostic sequence for vented, condenser, and heat-pump dryers, the safety recall history relevant to older machines, the component replacement procedures, and the regulations and standards governing tumble dryer safety in the UK. For related laundry appliance faults, see washing machine not spinning and washing machine leaking.

Key Facts

• Thermal fuse — a small one-shot safety device in the heating circuit that permanently opens (and must be replaced, not reset) if airflow is restricted enough to overheat the duct; the single most common single-component cause of "no heat, drum still turns"
• Thermal cut-out / high-limit thermostat — a resettable or one-shot device further along the airflow path that trips at a lower threshold than the thermal fuse; repeated tripping without addressing the underlying airflow restriction usually means the thermal fuse fails next
• Heating element — a coiled resistive element (vented and condenser dryers) that burns out with age, most commonly at the point where the coil contacts its mounting bracket; on heat-pump dryers there is no resistive element — heat comes from the refrigerant circuit and a "no heat" fault points to the compressor or refrigerant system instead
• Lint filter — must be cleaned every cycle; a partially blocked filter is the single most common cause of a tripped thermal fuse or cut-out and the leading contributing factor in tumble dryer fires
• Vented dryer exhaust hose — must run as short and straight as practical to the external vent; a crushed, kinked, or lint-clogged hose restricts airflow exactly as a blocked filter does
• Condenser unit (condenser dryers) — the heat-exchanger unit that must be removed and rinsed periodically (manufacturer typically recommends every 3 months of normal use); a clogged condenser produces the same overheating/no-heat symptom pattern as a blocked vent on a vented machine
• Door switch/interlock — many dryers will tumble with the door switch bypassed on some models for testing but will never energise the heater unless the door is confirmed closed and locked — a failing door switch can present as "no heat" even with a healthy element
• Drum rotation sensor — some models will not permit heating if the drum isn't confirmed turning (belt snapped or drive fault), since stationary heat against fabric is a scorch/fire risk — a "no heat" complaint can therefore actually be a drive fault
• Fire risk from lint build-up — London Fire Brigade and other UK fire services have run repeated public safety campaigns on tumble dryer fires; lint accumulating around or on the heating element is the leading identified cause
• Major UK safety recall history — Whirlpool identified a fire risk (lint accumulating around the rear drum seal and contacting the heater) affecting over 5 million Hotpoint, Indesit, Creda, Swan, and Proline tumble dryers manufactured between April 2004 and September 2015; a free modification programme began in September 2015, and following continued fires in un-modified units, the Office for Product Safety and Standards (OPSS) escalated this to a formal recall of an estimated 300,000–500,000 still-affected machines in July 2019; always check a machine's model/serial number against the manufacturer's recall checker before repairing an affected older unit
• NTC thermistor — on electronically controlled (sensor-drying) models, a failed temperature sensor can cause the control board to withhold heat entirely as a protective default, distinct from a physical thermal fuse failure
• Standard UK supply — most domestic tumble dryers run on a standard 13A fused plug/socket; heat-pump models sometimes need a dedicated circuit due to higher sustained load — always check the appliance rating plate
• BS EN 60335-2-11 — the particular safety standard for household tumble dryers (current edition BS EN IEC 60335-2-11:2022+A11:2022), sitting under the general BS EN IEC 60335-1:2023+A11:2023 appliance safety standard

Quick Reference Table

Detailed Guidance

Step 1: Isolate and check for fire risk indicators before anything else

1. Unplug the machine or isolate at the socket/FCU — confirm dead before opening any panel.
2. Check for any smell of burning, scorching, or visible melted plastic/discoloration around the back panel or filter housing. If present, do not attempt to restart the machine under any circumstances until it has been fully inspected and the cause identified and cleared.
3. Check the machine's model and serial number against the manufacturer's published recall/safety notice list if the machine is more than a few years old — several major UK brands have run large safety modification programmes for fire risk on specific ranges.
4. Only once isolation and a basic safety check are complete, proceed to functional diagnosis.

Step 2: Diagnostic tree

Tumble dryer not heating
├── Any smell of burning, scorching, or melted plastic?
│     └── YES → STOP. Do not restart. Full inspection required before any further diagnosis.
│
├── Check lint filter and full vent/condenser path FIRST (always, every job)
│     ├── Filter clogged → clean, reassemble, retest
│     ├── Vent hose (vented models) kinked/crushed/lint-packed → clear and reroute
│     ├── Condenser unit (condenser models) clogged → remove and rinse
│     └── All clear → proceed
│
├── Is the drum turning normally at full speed?
│     ├── NO / weak / stalling → treat as a drive fault first
│     │       (belt, motor, or rotation sensor withholding heat as a safety measure)
│     └── YES, drum turns normally → proceed
│
├── Test thermal fuse for continuity (isolated, multimeter)
│     ├── Open circuit (no continuity) → replace thermal fuse
│     │       → Also re-check airflow path — a blown fuse without a
│     │         restriction cause will likely blow again
│     └── Continuity present → proceed
│
├── Test thermal cut-out (TCO) / high-limit thermostat
│     ├── Open circuit → replace TCO
│     └── Continuity present → proceed
│
├── Test door switch/interlock for continuity when closed
│     ├── No continuity → replace door switch
│     └── Continuity present → proceed
│
├── Test heating element for continuity/resistance
│     ├── Open circuit / infinite resistance → element burnt out → replace
│     └── Continuity present, correct resistance → proceed
│
└── Electronic/sensor-dry model with all of the above clear
      → Test NTC thermistor resistance against manufacturer's chart
      → Test control board output to element during a commanded heat cycle
      → No output from board with a healthy element = PCB fault

Cleaning the lint filter, vent, and condenser unit

1. Remove and clean the lint filter after every cycle as standard practice — this alone prevents the large majority of airflow-related "no heat" callouts and fire risk.
2. On vented dryers, disconnect the exhaust hose at the machine and check its full length for kinks, crushing, or a build-up of compacted lint, particularly at bends. Clear with a vent brush or vacuum, and check the external vent cowl outside isn't blocked by debris, birds' nests, or a stuck flap.
3. On condenser dryers, remove the condenser unit (usually accessed via a front or side panel, secured by a lever or catches) and rinse thoroughly under a tap until water runs clear, checking the fins for compacted lint and fabric fibres.
4. On heat-pump dryers, clean both the primary lint filter and the secondary (mesh) filter that protects the heat exchanger — heat-pump models are particularly sensitive to airflow restriction because the heat exchanger fins are finer than a resistive element's open coil.
5. Reassemble fully and run a test cycle before concluding the fault is resolved — a marginal airflow restriction may need a full cycle to reveal whether the thermal cut-out trips again.

Testing and replacing the thermal fuse

1. Isolate power. Access is usually via the rear panel or, on some models, behind the lint filter housing at the front.
2. Locate the thermal fuse — a small cylindrical component with two spade terminals, typically mounted on or near the heater housing/ductwork.
3. Disconnect and test with a multimeter on continuity/resistance — a healthy fuse reads near-zero resistance; an open circuit confirms failure.
4. Fit the replacement matched by part number — thermal fuses are rated to a specific trip temperature and are not interchangeable between models.
5. Before closing up, always trace back and clear the airflow restriction that caused the fuse to blow in the first place — replacing the fuse without addressing the cause typically results in a repeat failure within a few cycles.

Thermal fuse replacement typically costs £6–£15 in parts and 20–40 minutes labour.

Testing and replacing the heating element

1. Isolate power. Access is usually via the rear panel; on some models the element sits within the drum housing and requires more extensive disassembly.
2. Disconnect the element's electrical connections (photograph first) and test with a multimeter — an open circuit (infinite resistance) confirms a burnt-out element; compare a working reading against the manufacturer's spec where available.
3. Remove the retaining screws/clips and withdraw the element, checking for visible scorching, a burnt-through coil, or lint fused onto the element surface.
4. Fit the replacement matched by wattage and part number.
5. Reassemble, restore power, and run a full test cycle, monitoring for correct heat output and checking the thermal fuse and TCO don't immediately trip again.

Element replacement typically costs £30–£70 in parts and 45–75 minutes labour.

Testing the door switch/interlock

1. Isolate power. Access the switch, usually mounted behind the door frame or front panel, reached by removing the top panel or a few screws around the door aperture.
2. Test continuity with the switch mechanically actuated (door closed position simulated) — no continuity with the switch pressed confirms failure.
3. Replace matched by part number, reconnect wiring, reassemble, and test a full cycle including confirming the door safety function still prevents operation when genuinely open.

Door switch replacement typically costs £10–£25 in parts and 30–45 minutes labour.

Frequently Asked Questions

My customer's dryer keeps tripping the thermal cut-out even after I've cleaned the filter — what next?

Check the full airflow path beyond the filter — the exhaust hose (vented models) for a hidden kink or crush point behind the machine, the external vent cowl for a blocked or stuck flap, and on condenser models the condenser unit itself for residual blockage even after a rinse. A cut-out that trips repeatedly despite a clean filter almost always means the restriction is further down the airflow path, not that the thermal cut-out itself is faulty.

Is it safe to keep using an older tumble dryer that's had a "no heat" fault fixed once already?

Only after confirming the underlying airflow cause has been properly addressed, not just the symptom (a replaced thermal fuse) — a machine that's blown its thermal fuse once due to lint build-up is a strong indicator the owner isn't cleaning the filter regularly, and the fault will recur without a change in maintenance habit. Also check the model/serial number against manufacturer recall lists, particularly for machines from the mid-2000s to mid-2010s, several ranges of which were subject to large-scale UK safety recalls for fire risk.

The dryer heats fine on some cycles but not others — what causes that?

Most likely a sensor-dry (electronic) model where the control board is deciding drying is complete or withholding heat based on sensor readings that don't match reality — check the NTC thermistor and, on models with moisture sensor strips inside the drum, check the strips aren't coated in fabric softener residue (a common cause of the sensor reporting "dry" prematurely and cutting heat early).

Do I need any special qualification to work on a heat-pump tumble dryer?

Yes, if the fault is in the refrigerant circuit rather than an electrical/mechanical component. Heat-pump dryers contain a small sealed refrigerant system, and any work that involves breaking into that circuit (as opposed to electrical or airflow diagnosis) requires F-Gas certification under UK F-Gas regulations, the same as for a fridge or air conditioning unit. Electrical and airflow diagnosis (filters, sensors, door switch, control board) does not require this.

Is it worth repairing a "no heat" fault on a dryer over 10 years old?

If the fault is a thermal fuse, TCO, or door switch, yes — these are cheap, fast repairs regardless of age. A confirmed burnt-out element is still usually worth repairing unless it coincides with other ageing symptoms (drum bearing noise, belt issues, PCB faults) that together approach the cost of a new machine, or unless the model appears on a manufacturer safety recall and the recommended action is replacement rather than repair.

Regulations & Standards

• BS EN IEC 60335-2-11:2022+A11:2022 — particular safety requirements for household tumble dryers, sitting under the general BS EN IEC 60335-1:2023+A11:2023 household appliance safety standard

• General Product Safety Regulations 2005 — underpins manufacturer obligations to notify and act on safety-critical faults, relevant to the major UK tumble dryer fire-risk recalls of the 2010s

• Electrical Equipment (Safety) Regulations 2016 — general UK electrical product safety framework applicable to domestic appliances

• F-Gas Regulations (UK) — govern handling of the refrigerant circuit in heat-pump tumble dryers; work on the sealed refrigerant system requires F-Gas certification

• Consumer Rights Act 2015 — sets the minimum statutory quality/durability position for domestic appliances, relevant when advising a customer on repair versus manufacturer warranty or recall claim

• WEEE Regulations 2013 — applies when scrapping rather than repairing the appliance, particularly relevant where a recall notice recommends replacement

• Electrical Safety First: tumble dryer fire safety — Electrical Safety First

• London Fire Brigade: white goods and tumble dryer safety — London Fire Brigade

• Product recalls and alerts (OPSS) — Office for Product Safety and Standards, gov.uk

• Recycle Your Electricals / WEEE guidance — gov.uk

• washing machine not spinning — comparable drive-fault diagnostic logic (belt, motor, sensor) for a related laundry appliance

• washing machine leaking — related laundry appliance fault-finding guide

• washing machine installation pricing guide — installation and connection pricing reference for laundry appliances