Dripping noise in toilet cistern

[19nffc77]

I have a dual flush toilet with a constant dripping noise coming from the cistern. I have looked in the cistern and can't see any drip, the water in there is undisturbed and there is no drip into the bowl itself but the sound is constant about 2 drips every second. I have looked through previous forums and can only seem to find posts where it's obvious where the drip is coming from. Can anyone tell me which part I need to replace?

 

[HERTS P&D]

Let the toilet fill up then turn off the isolation valve under the cistern, then check the water level after a few hours. Has the water dropped? If so then you have a faulty flush valve.

Or put dye into the cistern and see any drips of water int the toilet.

Andy

 

[just pumps]

Leave lid off and lay dry tissue paper around the bowl to show up any leaks, if paper stays dry then replace lid and check again. Water level looks low, does it flush waste away? If you find it leaks then under the large nut in top left corner is a rubber seal. Turn water off before removing the nut!

 

[19nffc77]

Thanks both for the replies. It turns out that I was looking in the wrong place, I couldn't turn off the water because the back of the unit is enclosed so I put toilet paper around the inside as just pumps suggested. I was checking for leaks at the back of the bowl but there is a small trickle of water at the front and it's constant. Does this then mean it's the flush valve that needs replacing? (Presumably the one on the right). If so how do I turn off the water to the toilet if the back is enclosed?

 

[just pumps]

Most likely within the enclosure and fingers crossed you will find one or turn house mains off and fit an iso valve somewhere, hope you are not on a water meter.

 

[19nffc77]

No, not on a meter so I suppose it will have to be the mains. Thanks for the help.

 

[HERTS P&D]

This is the part you need:

https://www.fixthebog.uk/ideal-stan...dual-flush-valve-diaphragm-seal-clip-sv01967/

Andy

 

[just pumps]

And what seal for the flush valve Andy. Which it might be.

 

[HERTS P&D]

And what seal for the flush valve Andy. Which it might be.

The one I quote above..............Or do you mean float valve?

Andy

 

[just pumps]

The one I quote above..............Or do you mean float valve?

Andy

My error.

 

[HERTS P&D]

I would replace the float valve with one of these:

https://www.fluidmaster.com/united-...aster-bottom-entry-fill-valve-12-brass-shank/

Andy

 

[19nffc77]

Great, thanks for all of the detailed information gents.