Siamp Optima 50 Won't stop filling

[gemius]

Hi
I fitted a Siamp Optima 50 flush valve a long time ago then in 2014 I replaced all the parts because it wouldn't stop filling after a flush. Now it's doing it again.
The overflow pipe lifts up when it's flushed but it won't drop down again of its own accord, so the cistern never fills.
I don't know why this should happen, except perhaps it is just an accumulation of grime.
Should I accept this as a normal life span and fit a replacement unit or is there an easy fix?

 

[gemius]

Further to the above I bought a new Flush valve and fitted it. The problem came from the cable to the push button which was not sliding freely through its sleeve and so would not allow the pipe to drop down. Why this should happen I don't know as nobody else seems to have this problem.

 

[CBW]

I’m not a fan of cable valves, they can catch on cistern, or fail as yours has.

 

[gemius]

Thanks for that Chris. If I ever have to fit another I'll bear that in mind.