How A Tumble Dryer Works
This is how the tumble dryer functions; it is not intended as repair guide. There are three basic types of tumble dryer:
- The blower tumble dryer
- The condensing tumble dryer
- Auto-sensing tumble dryers
All share basic characteristics, as follows.
Consider the machine as an air pump at all times. Apart from occasional belt breakages, almost all problems with dryers relate to air flow.
1) The machine sucks in cold air via a fan mechanism and passes it over or through a heater into the laundry.
2) The tumbling of the drum causes the clothes to fly through the hot dry air being blown or sucked in.
3) After passing through the clothes, we now have cooler, damp air. This may be:
a) Blown out of the machine, sometimes through a venting hose.
b) Passed through some form of condenser to convert the steam back to water and be collected for disposal later.
4) Auto-sensing machines will use a resistance circuit to determine the level of moisture remaining in the clothes. A damp load produces less electrical resistance than a dry one and the electronics adjust drying time accordingly.
5) The last sequence of any drying programme involves the dryer running without heat, in order to allow the load to cool gently, theoretically reducing ironing.
6) All the while, some form of timer will be counting down and the drum should be tumbling.
7) Temperature is controlled by one or more thermostats, and will be limited by some form of safety device. This may be a thermal fuse, a single shot bi-metallic or a manual reset thermostat.
No Heat is the single most common failure on modern dryers, and is caused by a few simple things.
a) Not cleaning filters.
b) If the filter is in the door, not clearing the channel through the door
c) Not cleaning the monobloc condenser (the big aluminium thing). A shower head is good for this.
d) Overloading; this will effectively restrict air flow.
e) Interrupting the load after a period of drying to “see how its doing". If you MUST interrupt the cycle, select cooling for a minute or so first in order to take the heat off the element.
This outline will give you an idea of how your appliance functions; it is not intended as a repair guide. If you have any doubts, seek professional help. Whatever you do, PULL THE PLUG FIRST.