Overflow pipe blocking ballcock?

Depends on type. Here is the problem. 1. we can't see why it's catching for starters.
Then there are ball cocks
with brass metal arms and copper ball float,.
there are brass arm ones with a plastic ball float.
there are plastic arms with copper ball float
there are plastic arms with ball shaped plastic float
there are plastic arms with barrell shaped float.
there are the narrow type floats made for slimline cisterns my not suite yours unless of course it is slim line one. That's the problem.

Now to solve, change the syphon unit to one with built in overflow so itstead of relying on an outside fed overflow pipe it drains into the toilet bowl so preventing any risk of flooding so it's worth looking at changing the syphon unit.

Take a digi photo of the cistern clearly showing the type of existing syphon then go to plumbing store and show them the photo and explain the problem they may come up with the easiest and cheapest solution.

bob
June 2012