toilet cistern not filling?

if the water is going straight down into the bowl when the cistern starts to fill its a problem with the flush valve.

check the rubber seal on the flush valve is not faulty and that the flush valve is shutting fully once flushed.

if you hold the flush valve half way down and twist it it will come apart and you can check the seal.

hi-spec plumbing & heating (essex)
August 2009