Hoping someone out there can help me. Have just spent a fortune on having a new en-suite including a Geberit concealed system. This has worked fine for the first half dozen flushes, then.....god as gold flushed it and it wont stop flushing. Have removed the flush plate and turned the water supply off. Is there some adjutsment to make that will fix this problem or is it a replacement part. Can manage to get both hands inside the tank but haven't got a clue what I should be looking or feeling for.