Now I'm going to take that last post back - It definately IS the water in the catch-tray that causes the error. I guess the first time I tested this, it must have taken a while to reach the sensor, or for the sensor to work, possibly because the water I used the first time was from the sump, and therefore wasn't "clean" and not sensed as effectively as clean water.
I have put clean water in, got the error, took it out, no error, put water in again, and got the error back. I have done this several times to prove the point.
Now, what can be done about it ?
1. Stop the pan filling with water.
That's not an easy task. There certainly doesn't appear to be any leaks in the wash drum, pipework, or any other obvious places. One possibility is the "vents" in both sides of the wash drum. These allow steam to escape into the void between wash drum and outer cabinet, which must surely condense somewhere, but these areas have a great wad of sound insulation in them. Although I can't see any evidence of moisture on it at all.
2. Move the sensor.
Perhaps the sensor (when I find where it is !!) is set too low, it only takes about a cupful of water to activate the error sensor. Obviously the water in the sump will evaporate in time, but if the machine is used daily, I'm not sure allowing a bigger catchment will solve the problem, only the same omount of water willl evaporate each day.
3. Drill a hole in the pan to let the water out.
This might not be such a daft idea. At least I could put a substantial "drip tray", say a large flat tupperware dish under the machine. I could certainly get to that to empty it weekly a damn sight easier than taking the machine out to tip it up!
I think weighing things up - I'm going to go for option 3, drill a hole in the sump. I'd rather be lifting out a tupperware dish regularly than de-installing the dishwasher !!
Hope this helps....
Dave, June 2007