The 6555 has a flap at the entrance to the drain hose at the bottom of the drum (rather like a human epiglottis). It is sprung loaded in the closed position and its purpose is to stop the soap powder/liquid falling straight out of the bottom of the drum into the drain hose. The suction from the pump opens it when the pump is running. This flap can get gunged up so that it does not operate properly and reduces the drain flow.
As to cleaning it - here I have to admit that I have only watched it being done, but the front of the machine was removed (this involved taking the top off, tilting the machine back about 30° (resting it against the kitchen worktop) removing the ring which holds the "bellows" seal aginst the door opening, undoing several screws, removing the bottom front plate and moving the control panel out of the way. The bottom of the drum was then accessable, the hose clip was disconnected, the hose removed and the flap was then easy to clean.
It sounds more difficult than it was, but I'm sure that if you undo things in a logical order, it will all make sense.
Peter Neill, December 2005
