Toilet cistern filling as and when, what needs replacing?

[Mr Chibs]

Hi all

My cistern started making an droning noise a month or so back when filling, now, it's louder when refilling after flushing and it's regularly refilling by itself... very early in the morning.

Is it the 'float' device that's faulty or the flush valve?
Or would you normally replace both?

TIA

 

[just pumps]

Depending on the age, sounds like you are describing water hammer so that would be the fill valve.

 

[Combicert]

If you have an isolator where the toilet connects to the water then you could try turning the flow down as a temp measure... agree with above - fill valve most likely culprit

 

[Mr Chibs]

Thanks gents, and yes there's a knock/hammer sound.