Water leaking into toilet / hissing noise

8 Feb 2013
Reaction score
United Kingdom

I had my en suite shower room fitted around ten years ago.

Recently I noticed a quiet hissing sound from the toilet cistern which is concealed behind tiles, and a small amount of water constantly leaking into the toilet bowl.

It appears that the only access to the cistern is to remove the flush plate and access through the hole. I can't see any other access as everything appears to be sealed in behind tiles (see pic). The guy who fitted the en suite shower room has since gone back to Poland and I haven't been able to contact him.

I have taken the flush plate off and can see that there is a constant amount of water going into the (I assume) overflow pipe into the toilet bowl.

The manufacturer of the cistern is kkpol.com.

I found the following short animation video on their website (also on Youtube) called "how to remove the fill and flush valves and what to clean". I am not sure if following the instructions in the video would solve my issue, or if it is something else (eg a washer).

Can someone advise me is this issue is an easy thing to fix?

Any help would be appreciated.


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1. There are two possibilities for water running into the pan:
1a. The float operated inlet valve is letting water past. This then fills the cistern beyond the overflow level, and the overflow runs the water into the pan.
1b. AND / OR the flush valve is letting water past into the cistern even when no flush has taken place.
2. The video shows you how to remove the inlet valve (first part) and the flush valve - second half.
3. It also shows you how to change the inlet valve diaphragm washer (1:06), and the flush valve sealing washer (1:40).
4. Note that the change of inlet valve part shows how to isolate the water and disconnect the inlet valve from the supply.
5. I don't know where in the UK you can get spares for these Polish items, but I'd suggest taking the old ones into a decent plumber's merchants and seeing if they have replacements.
Hi again.

Thanks for the previous advice.

I have removed the inlet valve from the cistern - see pics.

I cleaned the blue filter (A on pic)

I was not able to access the washer under part B as the plastic covering is screwed on so tight I cannot remove it.

When I put the part back into the cistern and reconnected the water pipe, the cistern would not refill. No water is moving through the part. I am not sure if I did something that would prevent water passing through, (the cistern was refilling before I removed the part). I tried putting the blue filter in different positions, and also removing it completely, but the cistern is still not refilling.
When I turn the water on when the water pipe it is not attached to the unit, the water comes out fine (E on second pic), but when attached to the unit it stops, and the cistern does not refill.

If I could access the washer under B in my pic, this could possibly solve the issue. Is there a way of loosening an overly tight plastic nut without breaking it?

If this is not possible I will have to buy a replacement part. I don't think that the manufacturer makes exactly the same part anymore. However, I have found online what appears to be a very similar looking/size one by the same manufacturer which I think would work (see 3rd pic).

The clip (C in my pic) attaches the unit to the socket (D on pic) on the back panel unit.

If I go to a local plumbing shop, would a similar part from another manufacturer work OK, or should I buy the one online?

Again - any advice appreciated.


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1. If you have removed the inlet valve already, the easiest route is to replace it with another side entry fill valve. E.g. Screwfix 49088. However, you would need to check it physically fits, that the float won't catch on the side of the cistern, and that the inlet flexible hose will connect to the valve.
2. Cleaning the filter will not have solved the problem. If you want to retain the existing valve, you will have to undo the white nut. I'd suggest a pair of grips. With the threaded shank pointing towards you, grip the body in one hand, put the jaws of the grips on the white nut and turn it clockwise. If it breaks, you are little worse off than at present.
3. Don't forget 1b in my previous post. It may not be a problem with the float valve at all.

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