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George-Allsorts, Senior Appliance Technicial Manager
Category: UK Appliance
Satisfied Customers: 1448
Experience:  Senior Service & Technical Manager at Allsorts Recycling & Appliance Repairs
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My Knight gas drier stops heating after about 30 secs of

Customer Question

My White Knight gas drier stops heating after about 30 secs of running. The drum does continue to rotate and cold air is blown through it.
JA: I'll do all I can to help. How long have you been dealing with this?
Customer: Its been doing this for some time now.
JA: Do you plan on doing the work yourself?
Customer: If it's possible I'd like to do the work myself. I've managed to fix the washing machine and dishwasher, but they're 100% electric.
JA: Just to clarify, what's the make and model of your dishwasher? And have you run a diagnostic test cycle?
Customer: It's not a dishwasher it's a tumble drier. White Knight BG447
JA: Anything else we should know to help you best?
Customer: No I think that's it.
Submitted: 3 months ago.
Category: UK Appliance
Expert:  Kelly replied 3 months ago.

Hi, welcome to Just Answer. My name is ***** ***** I look forward to helping you!

Please know that I am not compensated for my time by the site until you rate using the stars at the top of your page. A rating is appreciated once we get to the solution for your appliance issue, thanks!

It sounds like it is overheating and shutting off. Does the heat ever come back on after it initially stops?

Customer: replied 3 months ago.
It can be restarted either by opening and closing the door or by resetting the timer. It doesn't ever get very hot as the burner doesn't run long enough, the exhaust gas doesn't get particularly hot either.
Expert:  Kelly replied 3 months ago.

It may not feel hot at the exhaust. Does the heat cycle on and off or it never comes back on after it shuts off initially?

Customer: replied 3 months ago.
The heat cycle never comes back on by itself once it has shut off. It only ever comes back on by opening and shutting the door or by resetting the timer.
Expert:  Kelly replied 3 months ago.

May I please have your model number so I am able to provide you with accurate, model specific information?

Customer: replied 3 months ago.
It's a White Knight BG447.
Expert:  Kelly replied 3 months ago.

It sounds to me like a timer issue with intermittent contacts.


Customer: replied 3 months ago.
In that case I'll see if I can source a new timer
Expert:  Kelly replied 3 months ago.

Thank you.

Customer: replied 3 months ago.
Timers cost £51, which is quite a lot especially if the problem lies elsewhere, such as one of the thermostats.
Expert:  Kelly replied 3 months ago.

The thermostat would not shut it down and never come back, though. The timer has to be stopped to get it to work again.

Customer: replied 3 months ago.
if one of the thermostats were faulty, as soon as the temperature fell back into their operating range the heating would re-start?
Expert:  Kelly replied 3 months ago.

The thermostats open when they get hot, close when they cool. If they do not close to initiate heat when the dryer is blowing cool air, stopping the dryer would not have an effect on them.

Expert:  George-Allsorts replied 3 months ago.

Test the Thermocouple too... If the Thermocouple is defective, the appliance will light to start but then if it does not create the signal required the flame will go out and the appliance will cool down. you should get aound 30mv when hot.

Customer: replied 3 months ago.
OK I'll test the thermocouple, and the thermostats before trying a new timer.
Expert:  Kelly replied 3 months ago.

There is no thermocouple, this dryer used electric ignition.....

Customer: replied 3 months ago.
OK, I'll order a timer.Thanks
Expert:  Kelly replied 3 months ago.

Thank you.

Expert:  George-Allsorts replied 3 months ago.

My apologies for interjecting once more; I am only offering you checks that can be made before spending out large amounts of cash here..

The BG447 has the Flame Failure Electrode and the thermocouple... Either of these two can be the issue here

Go to the flame control unit and make sure all connections are clean and tight:

  1. check that terminal 10 is grounded properly to the cabinet (no earth here will prevent the thermocouple from operating)
  2. check the continuity and connection of the Flame Failure Electrode and terminal 9 (if there is no continuity the flame will fail)
  3. check that the thermocouple on the heater box is clean and in good condition, is earthed properly to the heater box, and check its continuity through to terminal 11 on the controller (if there is no continuity or a bad earth the flame will fail)
  4. disconnect the thermocouple from the controller and test that the thermocouple is sending roughly 30mv when heated (if there is no signal the flame will fail)
  5. reconnect the thermocouple to the controller unit terminal 1, ensuring a good solid connection.

A bad earth, faulty continuity, dirty or burnt electrode, or a dirty or burnt thermocouple on the heater box, can cause this issue

The full sequence flame controller opens the tandem solenoid gas valves after a delay time of about 8 seconds
and operates the pulsing spark ignition. If the flame is not detected by the flame failure electrode within 10 seconds
then the valves are closed. The system must then be reset by switching the machine off and re-starting.

The thermocouple on the heater box will disconnect the Flame Failure Electrode if it senses no heat within 30 seconds

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