the cistern in question is a Derwent macde,Pacific dual flush valve which i have just replced because the old one was weeping into the pan.the new one that just twists and locks into place has the odd weeping moment now and again but also does not want to flush if the cistern has been left overnight.if you take the valve out the next day then replace it to fill up it will flush ok untill its left for a period of time.any surggestions please,thanks very much

darren, October 2007

If the drain pipe has/is inserted too far, the seal at the bottom is forced up slightly, which prevents the cistern filling up as the water escapes into the internal overflow. Isolate water supply, empty cistern, loosen the compression fixing and ease the pipe out slightly until the seal shuts. Tighten the compression fixing etc.

Martin, July 2008

make sure the flush pipe (the large white one that fits into teh bottom of teh cistern) does NOT go into teh cistern by more that 30mm. If it does it gives symptoms you describe.

Listys Dad, November 2007