We recently bought a new Carthago Chic C-Line I50; lovely. Unfortunately I have discovered a conundrum. I had a problem with the full to 20% fresh water drain down which Southdowns have fixed. Today I filled the water tank watching the level and re- checked the drain down to 20% and the operation of the taps, shower and toilet; all worked well and I decide to fill the tank fully. As expected there was no visible leaks and I watched the electronic gauge get to 100%. I then left it filling expecting to see the tank begin to overflow underneath the van. I waited and waited but my drive remained dry; no water showed . The tank gauge kept showing 100% and visibly the semi-opaque tank was full but the water kept flowing in and I have no idea where the excess it was going. Can any of you good people throw any light on this mystery? I am concerned that it is filling up the underfloor but I can see no evidence of this.