toilet cistern - new flush valve has changed its behaviour

[Worrier61]

Hi
I recently (few months ago) accepted defeat and fitted a whole new valve (flow master). It worked beautifully and I could hear the column drop and seal. A beautiful sound because the previous one didn't seal properly (don't worry, all sorts of issues!)
Anyway at present the issue is that it does not drop until all the water has drained, so there is no such thing as a short flush or full flush. It just completely empties. Also the problem anyway with this type of seal is that it is helped by sheer weight of water so if cistern is totally empty it sometimes just simply won't fill. Family complains and I have to urge them just to press button a few times in the hope that it seals again.
What has changed and why won't the column drop sooner? At present it is using more water than necessary and also taking very much longer to refill (because of empty starting point)
Many thanks

 

[kidgreen61]

Does the cable have too tight a bend in it?
Simple things like that will cause problems.

 

[Worrier61]

OK, thanks for that. I don't think that is the issue as the button springs back fine. It's as if the plastic column has just a bit too much friction with its surroundings, or it's a flow/vacuum type issue and it simply can't fall. Maybe I'll take it out and refit. Can't remember if I just twist it out. If it is fitted from below then I'm not going there (close coupled etc)