White Knight E04 tumble dryer: what it means & what to check

Stop using it for now. Carrying on with this fault risks further damage or a leak. Switch it off at the wall until it has been looked at.

What E04 actually means

E04 is not a single fault across this range. On the heat pump model the control board is reporting that it cannot see the compressor — usually a disconnected or poor compressor connection, or a break in the wiring back to the board. On the condenser/vented dryers the same code points at the heating circuit: bad heater connections, a heater that has gone open circuit, or a break between the heater and the board. On the washer-dryer models in this group, E04 is listed as overflow — too much water detected in the machine. In every case the control stops the programme, so you either get damp laundry at the end or a cycle that halts part way.

What E04 looks like on a White Knight tumble dryer

Most people find this page having searched for what the machine is doing rather than the code itself. On a White Knight tumble dryer, E04 usually shows up as one or more of these:

Machine not draining
Water left in the drum at the end of the cycle
Stops mid-cycle full of water
Standing water in the bottom
Not filling with water
No water going in
Takes for ever to fill
Stops right at the start of the cycle

Recognise any of those? That is this fault, and the rest of this page explains what causes it and what you can check yourself.

What usually causes it

Loose or partly unplugged connector at the compressor (heat pump model)
Failed heater element or a loose heater connection (condenser and vented models)
A break in the wiring between the board and the heater or compressor
Too much water in the machine, on the washer-dryer versions
Main control board fault, once the wiring and component check out

What you can safely check yourself

Work through these in order. Anything beyond this — panels off, testing parts, anything to do with the wiring — is an engineer's job, and not one to attempt with the machine plugged in.

Turn the machine off at the wall for a minute, then switch back on and restart — a one-off glitch will sometimes clear.
Clean the fluff filter and, on condenser models, rinse the condenser out. Blocked airflow is a common cause of poor drying and it is worth ruling out before an engineer attends.
Empty the water tank if the machine has one, and make sure the drain hose is not kinked or trapped behind the machine.
If the code came with water on the floor, switch off at the wall and turn off the water tap before doing anything else.

Which White Knight models show E04

E04 means the same thing on all 4 of these models. If yours is not listed, the explanation above still applies — the code is set by the control board, not the model number.

WK-AT7WM148W · WK-AT8CW · WK-AT8HPW · WK-ATBIWM814W

Common questions about White Knight E04

What does E04 mean on a White Knight tumble dryer?

The machine has lost sight of one of its main working parts and has stopped the cycle rather than carry on — on most of these White Knight dryers that means the heating side, and on the heat pump model it means the compressor. E04 is not a single fault across this range. On the heat pump model the control board is reporting that it cannot see the compressor — usually a disconnected or poor compressor connection, or a break in the wiring back to the board. On the condenser/vented dryers the same code points at the heating circuit: bad heater connections, a heater that has gone open circuit, or a break between the heater and the board. On the washer-dryer models in this group, E04 is listed as overflow — too much water detected in the machine. In every case the control stops the programme, so you either get damp laundry at the end or a cycle that halts part way.

Can I fix White Knight E04 myself?

There are 4 checks you can safely do yourself first.

Turn the machine off at the wall for a minute, then switch back on and restart — a one-off glitch will sometimes clear.
Clean the fluff filter and, on condenser models, rinse the condenser out. Blocked airflow is a common cause of poor drying and it is worth ruling out before an engineer attends.
Empty the water tank if the machine has one, and make sure the drain hose is not kinked or trapped behind the machine.
If the code came with water on the floor, switch off at the wall and turn off the water tap before doing anything else.

This one usually needs an engineer once you have tried them.

How much does it cost to repair White Knight E04?

£66 including VAT for an engineer to come out and diagnose it, or £84 in total including VAT if it is put right on the visit and no parts are needed. Any parts needed are quoted on site before we fit them — you decide. Every repair carries a 90-day workmanship guarantee.

Tried the checks and it's still showing E04?

This one usually needs an engineer once you have tried the checks above. Then it wants someone who can open it up.

What it costs, before you call: the price is the same whatever the fault turns out to be — £66 including VAT for an engineer to come out and diagnose it, or £84 in total including VAT if it is put right on the visit and no parts are needed. Any parts needed are quoted on site before we fit them — you decide. Every repair carries a 90-day workmanship guarantee.

Our own engineers, not a call centre. We cover Nottinghamshire, Derbyshire and Leicestershire — most tumble dryer faults are seen same day or next day.

Call 0115 648 0929 Book online — postcode and number is all we need

Outside our area? The explanation above still stands — take it to a local engineer and tell them the code. Knowing it saves them time and you money.

Other White Knight tumble dryer codes

All White Knight fault codes and repairs →

What this looks like when it happens

tumble dryer not heating

Repairs we cover near you

Written by the engineers at ASAP Repairs, 0115 648 0929. We repair these machines for a living in Nottinghamshire, Derbyshire and Leicestershire.

White Knight E04 error — tumble dryer