It is extremely common for field service people to have to deal with problems arising from overloading, just pure and simple overloading causes a multitude or performance issues on washing machines and washer dryers. Here I will try to explain what it is and why it is absolutely vital that you do not overload your washer.
It is well known that to effectively remove dirt and staining you need three basic ingredients, heat to loosen the dirt and activate any detergents, motion to shake the particles of dirt free and the detergent to lift the staining. Obviously the process is far more complex than that with far more ingredients used in the detergents, but essentially those are the three basics you have to have.
Remove any one of them, or impair the ability of one and the performance will suffer as a result.
Overloading a washing machine can cause a number of issues some immediately apparent and some take time to manifest themselves it is therefore absolutely vital, if you want your machine to last and to perform at its best, that you load the machine correctly.
The diagrams below show balls inside the drum of a washing machine:
As you can see, where there are a lot of balls and they''re all solidly packed in (Fig. 1), there is no room for movement. Whereas in the second picture (Fig. 2) you can see that the balls, as they are not packed in tightly, are free to roll around the drum. The same basic premise applies to the laundry in your washing machine, if there's not enough space the it cannot move.
To successfully wash laundry it has to be able to move around inside the drum, allow the water and detergent to reach all the clothing and distribute evenly, not just for the best results, but also for the machine to work correctly and have as long a life as possible.
This raises several issues with the laundry not least of which are that the water and, therefore detergent, cannot get to the laundry to do its job. In fact, if you packed clothing in like this (Fig. 1) it isn't inconceivable that the garments in the centre would not get wet in extreme cases let alone the detergent and motion severely hampered from doing their job.
Also the load placed upon the bearings of the machine is massively increased and can cause premature bearing failure in the washing machine or washer dryer.
Clothing can also be pushed forward and effectively "lodged" between the inner drum and the door seal of the washing machine and dragged around causing marking and/or tearing of the clothes as they are forced around between the rubber of the door gasket and the lip of the inner drum. You will often see the first signs of this happening as smaller items (like socks) will get pushed into the area between the door glass and the door seal and sit there for the whole wash.
When overloaded the washing machine's performance and the wash results are severely reduced as I've explained but there's yet another factor, the dosage of detergent assumes a "normal" wash load and so there isn't enough detergent in the machine to remove the dirt. So your clothes don't get cleaned properly.
This problem only gets worse though as, because the water isn't getting to the clothes correctly we often see white marks, detergent residues, on the clothes as the water isn't getting to the detergent correctly to dissolve it. This is a very common complaint, often seen as white marks on clothes, or "white streaks" and all it really can be is overloading that is causing the issue. But if this detergent is left to sit there on wet clothing and it is a bleach containing detergent, then there is a danger that the clothing could be irreversibly damaged by bleaching.
Simple isn't it, or seems so. You get a bunch of clothing, sheets or whatever you need to wash and just rattle it into the washing machine, add detergent in whatever form, switch on the washer and let it go.
If only it were that simple.
There are related articles below that explain more about separating coloured and white items at the very least for starters, but here it's just an explanation of how to physically load the machine.
For larger items, such as sheets, you should try to feed the item into the washing machine drum in a feed around the drum. This is not particularly to help distribute the weight of the larger items correctly, although it does help in this regard especially with large bed sheets, but more to ensure that the item is not one big "lump" and that the water and detergent can get to it all and do the job correctly.
This photograph shows the drum loded correctly, note the gap
In any event you should leave an approximate 10cm gap between the top of the laundry to the top of the door opening for the drum, or a handwidth as a rough guide to ensure that your clothes actually get washed and not just wet and refreshed.
You should also add enough laundry so as not to incur an out of balance load. In most modern washing machines small loads and single items will not spin due to teh balance sensor.