On 18/02/2017 10:06, NY wrote:
"DerbyBorn" wrote in message
2.236...

cistern.

You could test this by purposely holding the ball-valve down and
overfilling it.

+1

Very likely. Could even be overflowing down the back of the cistern if
the
overflow pipe is blocked (presuming it is the type that needs one)

How else would excess water from a dripping ball valve escape if not
through an overflow. How does the other type of cistern work which
doesn't need an overflow? Is it possible/legal for the overflow to drain
into the normal outflow from the cistern to the pan? If it is, I'm not
sure why all cisterns don't have this sort of overflow.

A lot of cisterns don't have external overflows these days but overflow
into the pan. Bad idea if you're on a water meter because you're less
likely to notice that it's overflowing.
--
Cheers,
Roger
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