This article will outline the drying functions of the combination washer dryer. The wash functions are as explained in The Washing Machine General Principles.
There are two types of drying systems used;
Both types share the following common features:
The vented washer dryer does not re-circulate the air. It draws fresh air and passes it through the clothes as with the condensing machine, but vents the warm air out of the machine.
Neither system is as efficient as a stand alone tumble dryer, because of the size of the drum. This is considerably smaller than that of a tumble dryer, and as a consequence laundry, especially large items cannot "fly" in the warm air very well. This also why the drying load is generally limited to approximately half that of the wash load.
This outline is not intended as a repair guide. Beyond basis maintenance, we recommend professional assistance. If you're determined to repair it, UNPLUG IT FIRST!
Most washer dryer problems will generally be the same as or similar to the main problems that you get with washing machines because, as a washing machine, there is actually littel difference in the basic premise of both washing machine and washer dryer.
Where a washer dryer differs is in that it will have a drying section including a dryer heating element, additional thermostats to control that, a fan motor to drive the air and normally what is referred to as a condensate chamber.
When the tumble dryer section fails to operate the top problems are either tripped thermostats as they operate in the same manner as a normal tumble dryer and will cut out or indeed burn out if the door is opened before the cool down phase is completed. And, the condensate chamber becomes blocked with fluff or lint which restricts airflow.
If you have an issue with the tumble dryer side of your your washer dryer and want to attempt to repair it yourself, these places are where to begin looking for problems as they are the most common points where you get issues.
Fair warning though, on most washer dryers the condensate chamber is normally not the easiest thing to get to and clean so we would normally recommend that you get an experienced appliance engineer to look at it. For more advice you can use the washing machine machine forum.