Toilet cistern inlet valve keeps on leaking

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DrMoreau

2 posts

Wannabe Geek

#285844 20-May-2021 20:49

Hi everyone, have been having a few issues with a leaking cistern inlet valve.

We have recently purchased a 1930's bungalow and I have replaced some leaking 15 mm copper water pipes that feed into the toilet cistern with 16 mm PEX pipes. Since doing so, the inlet valve for the cistern has been constantly filling, resulting in water flowing into the overflow and into the toilet bowl.

I have replaced the small washer on the inlet valve, but it hasn't made a difference. If I lift the float up with a bit of force I can stop the flow of water, but this amount of pressure can't be applied by just the float without any assistance. I have tried bending the copper float arm to get this effect but to no avail.

My questions are: Has replacing the old pipes with a larger diameter changed the amount of water pressure reaching the cistern? And if so, do I need some kind of pressure reduction valve to get it working again properly?

Or, is it simply a failed inlet valve that needs to be replaced?

Any help would be greatly appreciated :)

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timmmay

18489 posts

Uber Geek

Trusted

Subscriber

#2710356 20-May-2021 20:59

I used to try to fix things like that. Now I just call a plumber.

Technofreak

5414 posts

Uber Geek

Trusted

#2710363 20-May-2021 21:23

I think it's possible you have dislodged a piece of debris that is now stuck on the valve seat (rubber/neoprene washer) and not allowing the ballcock to close properly.

The other option is you have caused the washer to sit in a slightly different position by bumping the valve while changing the pipes. The washer will have a wear ridge which is no longer aligned with the seat it sits against.

Ballcock washers are easy to change and that's probably the best option as you'll need to pull the valve apart to clean it so you might as well put in a new washer. You can buy them at a plumbing store or Mitre 10.

Turn off the tap feeding the cistern, using a a pair of long nose pliers, carefully straighten and take out the split pin ( you will want to reuse it) where the ball arm pivots, slide out the arm as well as the washer. Insert a new washer, refit the arm reusing the split pin. Adjust the arm to get the water level you require. Job done.

It'll take you about twice as long as it did for me to write this reply.

EDIT: I see you say you've replaced the washer. There's no much else to go wrong with these valves. I'd take the washer out and check inside the valve housing for anything that might be stopping the washer from seating properly.

P.S. I doubt the different size pipe is you problem. It will increase flow but shouldn't affect pressure. You could try turning the tap feeding the cistern toward off by a couple or three turns but then again that will really only affect flow unless it's almost right off.

P.P.S Has the valve twisted around somewhat when you fitted the new pipe? If it has the arm will not be moving vertically but instead moving up and down on an angle which may mean it is catching or jamming as the water puts pressure on the ball.

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farcus

1265 posts

Uber Geek

#2710413 20-May-2021 23:45

DrMoreau: Hi everyone, have been having a few issues with a leaking cistern inlet valve.

We have recently purchased a 1930's bungalow and I have replaced some leaking 15 mm copper water pipes that feed into the toilet cistern with 16 mm PEX pipes. Since doing so, the inlet valve for the cistern has been constantly filling, resulting in water flowing into the overflow and into the toilet bowl.

I have replaced the small washer on the inlet valve, but it hasn't made a difference. If I lift the float up with a bit of force I can stop the flow of water, but this amount of pressure can't be applied by just the float without any assistance. I have tried bending the copper float arm to get this effect but to no avail.

My questions are: Has replacing the old pipes with a larger diameter changed the amount of water pressure reaching the cistern? And if so, do I need some kind of pressure reduction valve to get it working again properly?

Or, is it simply a failed inlet valve that needs to be replaced?

Any help would be greatly appreciated :)

a while back I was having the same problem that was driving me nuts.

In the end I got one of these . . .

https://www.mitre10.co.nz/shop/plumb-it-universal-inlet-valve/p/289655

problem solved - and much quieter also.

Bung

4546 posts

Uber Geek

#2710415 20-May-2021 23:57

If you do have the older brass bodied ballcock there is a separate stainless steel nipple that the small washer seals against. If that is loose the water can leak past it bypassing the seal. The nipple screws into the valve from the end where the external pipe connects. If it is even older it may not be a separate item but then the end that should seal probably will be corroded and rough.

DrMoreau

2 posts

Wannabe Geek

#2712500 24-May-2021 17:41

Thanks for the replies. I had another look at the inlet valve to check if it was all aligned as it should be and it all looked good, and where the washer formed a seal with the plastic nipple all looked like it should work too. After scratching my head for a while to try and figure out why it was still leaking, I decided to go and buy a new inlet valve for $22 from the local hardware store. After 15 minutes it was installed and working perfectly! Lesson learned for next time.