Dual Flush Cistern making dripping noise, only when full

[ETAF]

I hearing a slow dripping coming from the cistern, but cannot find the leak/source

It looks exactly like this one
https://www.roperrhodes.co.uk/cisterns/comfort-height-cistern

I have turned off the water supply to the cistern and flushed the cistern and the drip Stops.

If i fill the cistern and turn the water supply off i can still hear a drip.

No sign of water under the cistern or anywhere around that area.

The water fills from under the water level, and i cannot see any movement in the water at all.

If it filled from the top, i would expect to see the water dripping , and suspect a ball valve
BUT that is not how these appear to work

Any ideas

 

[denso13]

If i fill the cistern and turn the water supply off i can still hear a drip.

Dripping in to the bowl? If you leave the supply to the cistern off, perhaps overnight, does the water level in the cistern drop?

 

[ETAF]

cant see anything in the bowl at all, and the water lever is 1/2" ish below the overflow pipe

I'll give that a go, mark the level and turn off the water to the cistern overnight, see what happens.
I wondered if it had something to so with the flow, as i did turn the water off on wednesday, to connect up some isolating taps, but that is the other side of the house , i'm refurbing the cloakroom. SO i may have turned the water tap on a bit more.
I tried reducing the flow to the cistern on the isolating valve - appeared to make no difference.
However, thinking what has recently changed , that was my immediate thought.

When the cistern has flushed and water off , there is still a lot of water at the bottom, but no drip
I tried twisting the flush assembly and reseating
I could take that out completely and clean around the seating area, probably do that tomorrow.

 

[denso13]

If you turn the water supply off and you can still hear a drip then it can't be the supply. If the cistern isn't leaking onto the floor then it only leaves the flush valve passing. You sure it is coming from the cistern?

 

[ETAF]

Thanks for the continued support

If you turn the water supply off and you can still hear a drip then it can't be the supply. If the cistern isn't leaking onto the floor then it only leaves the flush valve passing

Thanks It must be.
The sound is like a top fill dripping into the cistern.

You sure it is coming from the cistern?

If i turn off the isolating valve to the cistern and flush the toilet, NO drip

Putting my ear around close as i can and all the panels OFF
Sounds seems to be coming from the cistern

 

[dilalio]

Is it condensation dripping from the lid into the cistern?

Couple of photos of the setup might help us visualise things.

 

[ETAF]

thanks for the reply, NO its not condensation, not movement on water at all.
Strangely its stopped after i tried the things listed in previous post.
I'll see if it starts up again and if so, then I will reply to the post with some updates and images of the setup.

 

[ETAF]

Well its back again, as i went to bed i heard the drip , I will do some more investigation and post back here, in a couple of days, with more detail, images or if fixed what i found

 

[CBW]

Have you tried it with the cistern lid off?

 

[ETAF]

Thanks
Yes, its a small blue access point , as the link, and its off , so i can see inside the cistern, and look inside to see if i can see a drip, as i say, no movement on the water , that I can see.
thanks for all the support and suggestions

 

[CBW]

Do you have any food colouring? If yes you might be able to add some to the cistern and see if it shows up?

 

[dilalio]

Photos?

 

[Dansub]

ETAF. I know this is an old story. However I've got exactly the same problem with the same RR high level concealed cistern. Did you manage to find a solution and if so what did you do? Thanks

 

[ETAF]

i dont know , it sort of went away - but i have changed the drop valve itself and also cleaned up limescale and replaced the drop washer seals - as there has been a slow water flow into the basin - but with lockdowns and covid during that period , i was doing a few things on those toilets as i have 2 of them
also i have built a plinth - raised the toilet and redone all the waste since
sorry i cant be more specific

 

[Dansub]

Thanks for your very quick reply. I have just two further questions. I note that you twist the flush valve anticlockwise to separate and remove it. Did you have a problem in separating it and did it come out through the cistern access at the top okay?