How does a dishwasher work?

For those of you who have an interest in how machines work, this is just an outline guide on how a dishwasher does the washing up.These days, all modern machines are only connected to the cold water supply, which is then heated to the required heat, depending on the programme cycle selected.  The time for heating the water is taken into account in the timing for each cycle the dishwasher offers.

Unlike other machines, if you remove the lid of a dishwasher you will not see the works laid out as most of the parts are located within the door or under the stainless steel base. The machines are designed in this way to allow for the number of place settings required to be cleaned, otherwise we would only be able to wash a few cups and a couple of plates at a time.

The basic principle of a wash cycle is: cold rinse, hot wash, cold rinse, hot rinse, dry.  This is achieved by the water intake filling to the required level, controlled by a displacement of air into a diaphragm switch.  The water is then passed through a complex moulding of tubes and pipes to ensure water is moved to all the correct areas of the machine.

Once the water starts heating, the detergent needs to be released.  The heating of the water is then taken to the correct temperature.  As stated, the water is heated according to the wash cycle selected, the shorter the programme the cooler the water.  The more heavily soiled your items, the higher temperature cycles should be selected.

After the wash, the machine follows the same pattern but  the next cold water fill will call for the rinse aid to be added to ensure no residue is left on plates.  Rinse Aid is also used as it changes the water surface tension, making the load water repellent, resulting in the dishes being  as dry as possible at the end of the cycle.

As outlined above, the cold rinse is followed by a hot rinse, and finally the drying stage.

In order to give you the best result possible, you should always scrape plates to remove excess food and, if necessary, rinse off sticky substances under running water.  This not only gives you a better finish but also protects the filter from becoming clogged.

The most effective way of ensuring your machine gives you continued good surface is to ensure the filter is kept clean on a regular basis.  Also the spray arms should be removed and checked for blocking. 





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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