Repairing a tumble dryer

Jan 19, 2022 Last reply: 4 years ago 8 Replies

SWAMBOs tumble dryer is playing up seems to start OK but stops every so often and the condensate warning light flashes which indicates a full tank yet there is often very little water in it.



I have done the usual checks on the lint filter and heat exchanger and although there is some fluff about nothing that would affect operation. So tomorrow I am going to have a look inside. There is a small pump that takes the condensate up to the tank. So I will check the connecting hoses for blockages and try and determine if the pump is actually working I am not sure how the fullness of the tank is determined except that there is an overflow hose that seems to come back to the pump unit so I wonder it there is a sensor there?



I have looked at the exploded drawings on the Bosch website and there are only two sensors that I can see an NTC sensor which I presume is a thermistor which seems to be mounted in the heater element housing and a temperature limiter also in the same housing. Again I will try to determine if they are operational. I will hook up the NTC sensor to my DMM and see if altering the temperature affects the resistance. As for the limiter I presume cold it provide continuity only opening due to excessive temperature After that it would seem the control module could be the issue but the controls seem to be working OK and at nearly £340 pounds it is nearly about half the price of a new machine.



I would be grateful if anyone could point me towards which may be the likely villain of the piece and any other advice would be greatly appreciated.



Richard


You might want to mention the model number.

I can't see why the temperature sensors would produce a condensate full warning. On our 22 year old Miele, one of them had started to disintegrate, and that did give an intermittent fault.

Tricky Dicky explained :

The full water sensor sensor will be a float switch, operating a microswitch.

The tumble dryer is a Bosch Model No. WTE84307GB/12

Link to Bosch Spare parts page

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Richard

Thanks FredX I will have a go at that tomorrow morning and let you know how I get on.

Richard

Could there be a crack in the sensor which gets moisture inside before the tank is full due to condensation inside the machine. Brian

Is this a job for a wet and dry vac, or would that gobble up the float switch?

Update on the repair. Getting the machine up on a bench allowed me to see better into the heat exchanger cavity and there was considerable "felt" at the very back that I was able to remove, it had not blocked any orifices but there was quite a lump. Lifting the access hatch labelled 0509 revealed a little amount of lint but not as much as I expected anyway I cleared as best as I could working blind and relying on feeling things. Having cleaned as much as possible and before taking more of the machine apart I decided to test it and see if I had improved things. I threw a soaked towel in and set it on a 40min cycle and the machine completed the cycle without any hiccups and the towel dried. Whilst it was drying I could hear sound from the region where the pump is situated and at the end of the cycle there was a surprising amount of water in the condensate tank which I had completely emptied before testing so indicating a functioning pump and no blockages in the connecting hoses.

I am going to leave it at that and see how it performs. Thanks for all the suggestions.

Richard

Tricky Dicky formulated on Thursday :

:-)

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