Bosch Tumble Drier keeps tripping heater cut out

Our 6 year old Bosch WTA 2000 Tumble Drier keeps tripping it's heater cut out. Press it in and it runs ok (hot) for a while then trips out again. The filter is clean and the air vent at the back, which vents directly through the wall, is clear. So I imagine its a duff sensor yes/no?
I haven't had the back off yet, but befor I do, does anyone know if this an easy/difficult job?
Any other thoughts... Many thanks, Roy.
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Is this a little red button on the back panel ? If so it is a White Knight drier made for Bosch. Usual cause is lack of airflow, double check everything otherwise could be faulty motor fan, inlet stat next to heater or the cut-out itself.
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Many thanks for your response. Yes it does have a small red reset button the back.
I had the bottom part of the back off yesterday. I removed the flexible ducting pipe, to make sure there was no blockage. All clear. So unless there is a blockage deep inside the fan housing (unlikley I think) it looks like it's not down to lack of airflow.
I also blew out the small amount of dust that was around the motor etc...
From what I have read in other posts I think it could be down to two possibilities. The heater thermostat, or some other thermal sensing (fire protection) device somewhere in the system.
Yes/No?
I intend to remove the whole back later today to see what I can find!!!!
Many thanks, Roy
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Just spoken to the a local Bosch service/parts agent.
To have someone come out it's 60 + for first half hour.
There are three parts that might be duff... The heater thermostat, a cut out and an air temp sensor. Cost are about 32, 20, 22 ! I was expecting about a fiver each... Evidently the thermostat and cut out are not east to get to... Hmmm...
Praps I should just go and buy a new one... :-(
Roy
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They are very easy to change and White Knight parts would be in your price range.
Peter
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http://www.sparesrus.biz/ol-catlg/td-stat-01.htm
Peter
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Peter,
Many, many thanks for that!
I have the thing apart - see...
http://www.gillandroy.com/diy/tdrier
Click on small or big depending on your download speed...
A = the 12.95 Heater thermostat B = the 9.95 Manual reset cut out
The Exhaust thermostat is at the top of the URL you sent.
There is a drop down selection of cut outs on your URL. Any idea which I need given that the number on the cut out I have is 7M94605600C. There doesn't seem to be anything in the list like that..
I imagine the sensors all have defined temperatures at wich they switch. Do you know if that information is spelled out somewhere?
Would you advise I just replace them all while I have it apart? Or is there some way I can test these devices on the bench?
Many thanks for your help.
Roy
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The drop down list is just the models that part fits, it is the correct part for your model. The outlet stat would not cause the TOC to trip if faulty, it just knocks the heater off at about 60oC when the clothes are dry (to save energy), the heater stat controls the inlet temperature. Only other thing I notice is the red ends on the heater element, this can cause the TOC to trip if the appliance is in a confined space because they where rated for the wrong voltage and get too hot, replacements have blue ends so you can tell the difference.
Peter
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Yes - I sussed that just after I posted - d'oh..

So - unlikely to be that then...

So would that cause the cut out to trip if it were duff?

Now that's fascinating... My wife has always said that she felt that this machine got too hot. I told her not to be silly Well there is no worksurface over the top of the machine but there is a wall to the left and and a washing machine to the right. I was considering putting a worksurface over the top - perhaps I'll shelve that idea. No pun intended :-)
Perhaps I should put a new element in while I'm at it! http://www.sparesrus.biz/ol-catlg/td-element-02.php
I have been trying to contact Spares R Us but I think they must have gone on their Christmas Hols - can't say as I blame them!!
Many thanks for your help and have a good Christmas!!
Roy
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Peter,
Just one other point. In your earlier post you said it might be a faulty motor fan.. Where is this located and what could be wrong with it?
Many thanks, Roy
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It would be noisy as well usually, they slip on the motor shaft so don't blow properly. Easy to check and make sure no blockages etc, lower back panel off, four screws underneath cabinet hold motor bracket, pull out black plastic rivet from fan housing cover plate (round motor shaft) turn cover to release in direction of arrow, remove motor c/w fan.
Peter
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Hmmm - Hang on... perhaps I'm reading that wrong. Looks like the drop down is listing all the machines this part this satisfies...
Roy
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The drop down list is just the models that part fits, it is the correct part for your model. The outlet stat would not cause the TOC to trip if faulty, it just knocks the heater off at about 60oC when the clothes are dry (to save energy), the heater stat controls the inlet temperature. Only other thing I notice is the red ends on the heater element, this can cause the TOC to trip if the appliance is in a confined space because they where rated for the wrong voltage and get too hot, replacements have blue ends so you can tell the difference.
Peter
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The heater thermostat is on the heater backplate in the centre of the round metal sheathed element, you will see it when you remove the back of the machine. Check for good airflow from the vent hose when it is running and if it vents through the wall check the vent outside. If you need to replace the heater thermostat obtain a White DKnight one it will be alot cheaper !
Peter
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Peter,
Many thanks for your assistance with this one.
I replaced the Heater Thermostat and the Manual Reset Cut Out. Cost a little over 20 - a lot less than the 60+++ for a callout plus bits.
All working fine now...
You saved me a bundle...
I now have a little problem with the door catch - but I'll do another post about that...
Many thanks, Roy
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