Leaking Bottom Entry Cistern

Hi,
The cistern I have fitted to my toilet is a bottom entry one and its leaking.
Its a plastic fitting and at the moment I have a copper 'Isolating Valve' fitted straight into that, its 1/2" into the cistern and 15mm to the copper pipe feed from the water supply.
I took it all apart last night, there was a fibre washer where the 1/2" goes into the cistern, that had perished, so I replaced it, made no odds.I also replaced the isolating valve for one exactly the same, I still have the same problem.I think it might be the fact that the thread on the cistern intake is stripped-any thoughts?I could try cutting pack the intake and try again, but that might stretch the coper pipe.
I tried putting PTFE tape on it, I wound it same way as the nut did up-is that correct? I can never remember if you put it on the way the nut goes or against.

Is what I have described the correct way to do things? it was done about 10 years ago by a plummer.
Is there a better way of doing it? I like the idea of an isolating valve, but coper to plastic seems to be a pain.

By the way I am on Mains water pressure-No water tank.

Thanks

Steve

Thanks

Steve

Simplest solution might be to fit a new float valve. Plastic threaded tails often get cross-threaded and sometimes the plastic will crack, especially if the wrong sort of sealants have been used on it.

I always use flexible connectors between isolating valves and plastic threaded inlets to avoid stress and misalignment problems. You could do this if you cut back the copper pipe, fit a new isolating valve and connect with a flexi (some flexis have a built in isolating valve).

Copper/chrome to plastic is quite normal. If the thread is stripped as you say it could be cross threading, stopping the fibre washer from mating correctly. Sometimes you can re-shape the thread with a stanley blade or something so long as it is not too bad. If its not cross threaded could be that the washer doesn't fit properly. Does it fit over the hole correctly. Some fibre washers are too big/small for the fitting.
Suppose you could try cutting it back a bit and see how it goes. If that doesn't work, buy a new valve. Just be careful not to cross thread it when fitting it and also not to overtighten. The nut only needs to be hand tight plus a little turn with the spanner.

Hope that might be of some help to you

Thanks
Looks like I will go for a new cistern.Is it correct that the fitting into the cistern is 1/2"? I tried to fit 15 mm pipe last night, but it wouldn't fit!!
The fibre washer is the correct one as it came with the 15mm to 1/2" isolating valve, it just seems wrong..the 1/2" out of the isolating valve is short (@ 6mm I guess)the fibre washer is no real thickness, I guess I would expect some kind of gland, but no way is that going to fit with only @6mm to spare..

Steve

stevec59 said:

Looks like I will go for a new cistern.

Click to expand...

Why change the whole cistern? You just need a new valve! Also it sounds like you may have the wrong sort of isolating valve or something. Go for a flexi as I suggested.

Steve

The size of the connector is 15mm - 1/2" as you say because it is measured over the size of the hole and not the size of the thread it is connecting to. there are no glands, just the fibre washer and 6mm will be enough to stop the water when it is fitted correctly.

Rgds

Thanks squeaky and anyone else.
I must admit, I decided to get a plumber in,I wasn't too keen on doing too much more my self.
I am glad I did get plummer in, he had problems,he replaced the cistern valve, the old one did have bad thread on it,First one he put in was a ball type, but he couldn't get it to go in correctly, he said the ball was too big, swapped it over with my ball, still the same, so he put in a 'Off set' cistern value, but when he was fitting it, it broke,so then he went for something like a Torbeck Bottom Entry Cistern Valve, the one I got from Wickes, that fitted fine, connected up-Still leak, so I said how about fitting the isolating valve to the cistern valve first, so you get 100% good square sel, he did that and added some sealant, all worked well-And it didn't cost me the earth
I would have gone cray going through all that.

Once again-Thanks so much for advise.

Steve