Thermostat Failures on a Tumble Dryer

Reasons why a thermostat fails

The rate of flow of air through the tumble dryer can and will affect the operation of the dryer, and may well cause a failure of the thermostat itself.

In a normal drying cycle, the drum will rotate, and may even reverse the rotation.  They cycle will depend on the settings you choose, but a timer will be slowly counting down the drying time, either mechanically or electronically.

Cold air is drawn into the machine, this passes over or through a heater and into the drum.  The clothes will then be ‘tumbled’ through the heated air.  The resulting cooled air will then be either passed out through a ventilation hose, or through a condensing element.

If the air is blocked and not allowed to pass through the appliance, this will have an effect on the operation.  The tumble dryer can overheat and the safety mechanism will be tripped into operation, cutting off the power to the appliance.


Points to Watch:

The Filter

You must take care to ensure that you thoroughly clean the filter of any fluff build up at the end of each cycle.  You must always do this with care, and ensure you put them back in place correctly.  Never use the appliance if the filter has been damaged or broken.  

The reason for this is that fluff will build up and be forced into the air system, ending up on the heater.  One of the consequences of this is that the efficiency of your appliance will be affected but, more importantly, it is a major fire risk.  

What it does do is decrease the airflow, which converseley  increases the fire risk, as the temperature is not lowered as cooler air is not able to be drawn in.  Also, this hike in temperature can and will trip out the thermosat.

Door Channel and Vent Hose

Be aware that you when you remove the filter, you should check down through the door to ensure it is kept free from fluff.  

Another area to be careful of is the vent hose – this should be kept as short as possible.  A longer hose can be trapped behind units and the appliance itself, and may be crushed which would have a detrimental effect on the air flow.  You should also try to avoid allowing the hose to droop and form a U-bend, as this can fill with water, therby decreasing the air flow.

Loading the Appliance

Be careful not to get carried away and stuff as much laundry into the drum at one time as you can.  The effect of this is that the air will not flow correctly and far from drying all your washing at one go, you will end up drying and drying and drying as you have overfilled it.  Again the interruption in the air flow could damage the thermostat.

Condenser Dryer

If you use a condenser tumble dryer, you will be aware of the aluminium plates at the bottom of the appliance.  When the cover is removed you are able to see the front, and it is very important that this area is kept clean.

Spare Parts

If the need arises, it is fairly easy to obtain the correct spare part for your appliance, be it a motor or a thermostat, just remember to quote the make and model of your dryer to ensure you get the correct fit.  As well as being easy to obtain, they are fairly easy to replace as well – with a few exceptions.  

Please think of safety first and before you do anything at all you must disconnect the appliance from the power supply. 

Regardless of all the points mentioned above, the number one cause of a problem with a tumble dryer is the operator. For instance,  if you open the door and interrupt the drying cycle, the airflow stops and the temperature of the element briefly rises, causing the safety mechanism of the thermostat to trip.

If you realise you have put a delicate item in the tumble dryer that shouldn’t be there, before opening the door, turn the timer mechanism to cool, and leave it there for a few minutes before you open the door.  Once you have retrieved your precious article, just reset the timer and leave the rest of your washing to dry safely.







Disclaimer: The information provided has been prepared as a guide only and the steps taken are likely to vary for different appliance models. We strongly recommend using a qualified engineer to undertake major repairs and fault finding.


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