Fault Finding on Tumble Dryers
Before you can think about finding the reason for a fault, or to carry out a repair, it is a good idea to have a basic understanding of how this type of appliance works.
There are a few types of tumble dryer on the market including the condenser dryer, the heat pump tumble dryer and the vented dryer. A very brief description of each version follows:
The vented dryer needs a vent to push the hot air out of the area where the dryer is situated. A vent hose is required in order to remove this hot air, and is usually pushed out through a window, door, or even a cat flap!
The condenser dryer is self-condensing, which means that the moisture removed during the drying cycle is condensed internally and the water vapour is drained to the house drainage system, or collected in a container to be manually emptied.
The operating systems of both of the above types of dryer are similar and do not need specific explanations.
In order to perform as you require, the functions your dryer must have are heat, mechanical action and airflow. If any of these fail the dryer will not do what it is supposed to.
The most common areas for problems are the heater and thermostats. To identify the source of the problem, it can be determined by testing the heater elements for continuity, using an electric meter. If the heater is open circuit, it will require to be replaced but don’t forget to check both circuits.
If the heater is not open circuit and there is continuity, the next place to look is the thermostats. There are normally one or two mounted around the heater housing, however, there could be one or two others housed on this vent. This is generally known as the exhaust stat, however, its not that common for this to fail.
It is more than likely the overheat thermostats have failed or, in reality, have operated correctly, as this part is really a safety device designed to stop the tumble dryer from overheating and possibly catching fire. This generally occurs if the airflow is interrupted in any way. If the thermostat trips without any other problem being noted, it is probably caused by the drying cycle being interrupted when the door is opened mid-cycle, without the cool programme being selected first and left to run for a few minutes before the door is opened. If this not done, this action causes heat to build inside the dryer, tripping the thermostat.
Unfortunately, a lot of thermostats cannot be reset and will need to be replaced. Any tinkering with a tripped thermostat will only end up by the dryer catchinfire –it can be dangerous, do not do it. Parts are easily obtainable, easily fitted and do not cost the earth. Just make sure you have the make and model of your appliance available when purchasing spare parts to ensure they are the perfect fit.
The most important thing for an tumble dryer to work efficiently is to have an uninterrupted airflow. Any impingement on this will result in the unit overheating and, again, leading to fire if not resolved quickly.
In order for a tumble dryer to work it needs to be able to draw in cool air, which is heated and then passes through the clothes in the drum. The clothes are tumbled through the hot air allowing the clothes to gently dry. Once the heated air has passed through the clothes, the used air is either vented through a hose or passed through the condenser which will change the steam back into water.
If the appliance is unable to draw in the cool air, it will result in much longer drying times, which will increase your electricity bill. If you are experiencing this problem the first place to look will be the filters.
Blocked filters can affect the airflow and seriously affect the performance. Basically if you carry out routine maintenance and ensure filters are cleaned after each cycle, and replace damaged or broken filters, these problems will not arise and the good airflow will be maintained.
All types of dryers must have a good air supply around them or problems will arise. You may not have realised this could be a problem, as a dryer could work like this for some time, but sooner or later a problem will arise.
No heat in the tumble dryer
If your appliance does not heat, you could start by checking for a reset button – usually red and mounted on the back. You might find this resolves the issue. If that doesn’t work, you should work through trial and error process testing the following:
Heater might be faulty
One of the thermostats may have tripped or is faulty
Blocked up with fluff
Drum not rotating
A faulty belt is not uncommon for this problem, but check:
Motor capacitor, if you have one of these
Jockey wheels faulty
It is usually fairly straightforward to find the answer to this problem, but may not be that simple to resolve!
Jockey wheels faulty or worn
Felt pads worn
Faulty motor bearings
Dryer not starting
Not a very common problem these days but could be the microswitch failing. Possible it could be a timer failure, but not that likely.
Other problems you may encounter could include steam. Just check the condition of your vent hose, if that’s OK it could well be that if you hang your hose out of a window, the wind may be strong and is blowing the heat back up the hose.
If you notice any kind of bad smell, you should again check the condition of the hose, as water can gather in pockets a hose, causing the smell when it gets stale. Just replace the hose and the smell should disappear.
Self Condensing Dryers
These appliances are much more complex than the vented dryers. It is probably something for the professional to fix. Just check first that the condenser tray does not need emptying. Sounds silly, but it is amazing that you can just forget to check this.
From a safety point of view, do not forget to disconnect the appliance from the power supply before you attempt any repair. You should also ensure that you have a working smoke alarm in the area the tumble dryer is sited. Also, bear in mind, that all manufacturers recommend that you do not leave this type of appliance unattended when in use.
With a vented dryer, you will need to check that the hose is undamaged and is not obstructed in any way.