My toilet is hissing at me!

[atmosworld]

Hello,

I had a search before I posted for other 'hissing' posts, but none seem to have the same set-up as my cistern. A few weeks ago, it started hissing. I know nothing about plumbing or the names of parts - so please forgive me!

I thought it might be limescale. I removed the white part (with the green bits) - it was easy to remove and gave it a clean. I then replaced it, and for about an hour, the hissing stopped. But then it started again.

I went to remove the other white part (with blue) for cleaning, but I could not see any way to remove it.

There does seem to be very small amount of water going into the basin - I am guessing that is where the water is going.

If I isolate the water to the cistern, the hissing also stops.

Is anyone able to give me any advice on what I might try / part I need or order? Or do I require a plumber?

Also when I put the lid back on, screwing the silver button into the white part, is very fiddling as the white part keeps dropping down - is this normal?

 

[opps]

I am not a plumber....

It may be the case that the rubber washer under the green part need replacing.

If it is letting water run into the pan, the filler (blue) will be trying to play catch up and letting more water, albeit slowly, into the cistern. Hence the hissing noise because it is letting in high pressure water very slowly.

Looking at the photo, I don't think that the water level is too high.