I just bought a Samsung WW5000t ecobubble washing machine. It drains too fast for my drain pipes, giving flooding. I guess that it is because the volume of the drained water+air is larger than my previous washing machine with only water.
1) Does WW5000t has a drainage speed controller?
2) If not, would a mechanical drainage restriction cause harm on the pump in the washing machine? Since the pressure in the drainpipe will increase.
Have you checked that there are no blockages in your drains. This would mean lifting the manhole cover from your foul water pipes and visually watching the water drain away..it could also mean ther is a problem between the house and the outside drainage.