Contrary to popular belief, the dishwasher is a very simple appliance, with few moving parts. However, unlike most appliances (where removing the lid allows you to see the internal components), the dishwashers parts are buried in the door or beneath the machine.
To wash your crockery, the dishwasher will typically carry out a program like this:
Cold rinse, hot wash, cold rinse, hot rinse, dry.
To do this, the machine must do the following things:
Step1: Fill and circulate water. The water level is normally controlled by the displacement of air into a diaphragm switch. This is achieved by passing the water through a "baffle" or "matrix"chamber. This is a complex molding of tubes and chambers to direct the water into different parts of the machine. More about them later. Assuming fill, we should now get circulation.
Step2: At the hot wash stage, two additional functions must occur; firstly the addition of washing agent. This is usually accompanied by a "Thunk" as the detergent compartment opens. Secondly the water must be heated, typically to 65?C, although greater ranges are now available due to the use of digital control systems rather than fixed value thermostats. All modern dishwashers should be connected to the cold water supply only; as the heating time is included as part of the predetermined wash program. Also, consider that hot water is dirty water, and firstly will leave deposits in the fill part of the waterworks and, secondly, the wash program will be shortened by the reduction in heating time. This may well lead to reduced cleaning results.
Step3: Rinses are merely a repetition of the earlier steps, so further explanations are un-necessary.
Step4: The final hot rinse and dry sequence is when things get more interesting. To conclude the wash successfully, rinse aid is added. Ostensibly, this product is sold to improve the quality of the finish of the crockery. What it actually does is to destroy water surface tension, making the load water repellant. This means that there is no water on the crockery at the finish of the programme. It has not actually dried, despite the heat and the steam! A few dishwashers additionally have a fan arrangement to assist with condensing the steam away. During this last stage, water is released into the water softener unit from the fill chambers, ready for the next wash.
It is essential for good wash results that all filters and rotors are kept scrupulously clean. Also, heavy deposits on crockery and pots should be removed BEFORE they are put in the appliance.
This outline is not intended as a repair guide. Beyond basic maintenance outlined above, we recommend professional assistance. If you're going to repair it yourself, UNPLUG IT FIRST