Replace valve/washer/nut/seal for cistern water inlet leaking where nut meets porcelain?

ClarusDignus

NSG666 said:

You're welcome but now I've seen the additional photos, if I were doing it I'd probably buy the 500mm version of the flexi connector, cut the existing pipe back nearer the skirting, fit an isolator then a short bit of copper to connect between the isolator and the new flexi. You can get flexis with isolators but I don't like them so never used them.

Is the purpose of the isolator to turn on and off the water supply?

Can you recommend an isolator?

NSG666

Yes it's to allow you to turn off the water to the w/c without turning off the rest of the house during future maintenance. It depends on whether you want push fit or not. You can get flexis with a push fit end but SF only sell then in pairs.

Isolating Valve 15mm 2 Pack | Isolating Valves | Screwfix.com


JG Speedfit 15SVP Isolating Valve 15mm | Isolating Valves | Screwfix.com

Section62

ClarusDignus said:

Grenage said:

Surely that's a copper pipe hastily brushed with emulsion?

I'm assuming it's a plastic pipe only because it's grey where there's no paint, but I could be wrong. Could it be a plastic-coated copper pipe?

I'm pretty sure it is plastic.  Hand-bending copper to achieve such a uniform curve over that length requires considerable skill.

Whereas if plastic is yanked over hard enough it will naturally settle to a relatively uniform curve with very little plumbing skill needed.

But forced plastic pipe will exert undesirable forces on joints and connections, which is apparent in your pictures and could be partially overcome with a longish flexible connector as NSG suggests.  I'd agree with not bothering with one with a built-in isolator.

I'd also recommend if you make a new connection to the plastic pipe that your best chance of making it leak-free is to make it with a metal compression fitting using a copper olive.  That combination has the best chance of pulling the plastic back into a circular shape (if it has deformed), plus gripping the pipe firmly enough. But it is essential to also use the correct pipe insert for that make as per NSG's comment.


The waste connection should have a more gradual transition between the level of the bowl outlet and the soil pipe.  As it has been done it will be more prone to blockages.  If you needed to get a plumber in to fix the leak it might be worth having them refit the whole toilet properly... but if you are confident you can fix the leak yourself then don't worry about the waste connection unless you start getting blockages.

ClarusDignus

Section62 said:

I'd also recommend if you make a new connection to the plastic pipe that your best chance of making it leak-free is to make it with a metal compression fitting using a copper olive.  That combination has the best chance of pulling the plastic back into a circular shape (if it has deformed), plus gripping the pipe firmly enough. But it is essential to also use the correct pipe insert for that make as per NSG's comment.

Am I missing anything in this sequence?

1. Newly cut existing pipe by skirting
2. Copper olive
3. Copper pipe
4. Flexi connector
5. Brass shank of bottom-fill valve

ClarusDignus

NSG666 said:

It depends on whether you want push fit or not. You can get flexis with a push fit end but SF only sell then in pairs.

Thanks. I'll acquire these and report back. I presume the copper is ordinary copper piping.

ClarusDignus

Section62 said:

But it is essential to also use the correct pipe insert for that make as per NSG's comment.

When you say, "that make", do you mean the copper olive, and when you say, "the correct pipe insert", what would that be?

Section62

ClarusDignus said:

Am I missing anything in this sequence?

1. Newly cut existing pipe by skirting
2. Copper olive
3. Isolator
   
4. Copper pipe
5. Flexi connector
6. Brass shank of bottom-fill valve

As above.

The (compression) isolator might come with a copper olive already, but sometimes they are brass. You'll only know for sure when you've got it in your hand.  If brass, the copper ones can be purchased separately - usually in packs of 2 or 5 or something.

ClarusDignus said:

Section62 said:

But it is essential to also use the correct pipe insert for that make as per NSG's comment.

When you say, "that make", do you mean the copper olive, and when you say, "the correct pipe insert", what would that be?

The pipe insert is a piece of plastic which pushes into the end of the plastic pipe to strengthen it.  Each pipe manufacturer offers their own type designed for use with their pipe system.  E.g. like this -
https://www.toolstation.com/jg-speedfit-superseal-pipe-insert/p68773

If you are lucky there might be one in the end of the pipe already, but I wouldn't bank on it.  And it might not be reusable, but would give you a pattern to source a replacement one, assuming the plumber used the correct one for that pipe.

Alternatively, if you can read the manufacturers details printed on the pipe (but not covered with paint) that would be the surest way of getting it right and would enable you to buy one without turning the water off first.

ClarusDignus

Section62 said:

Also, when did the leak start, and was there something which happened immediately before which could be the cause?

I'm at the point where I've removed the old fill valve, scraped off the sealant around the hole in the bottom of the cistern and I'm testing the new fill valve. The water supply is off. I'm manually filling the cistern with a jug of water to test if leaking persists. Even with the new fill valve and locknut applied, droplets form at the same point on the outside of the cistern. The gasket doesn't seem to be sealing. Water is somehow getting past it.

Section62

ClarusDignus said:

I'm at the point where I've removed the old fill valve, scraped off the sealant around the hole in the bottom of the cistern and I'm testing the new fill valve. The water supply is off. I'm manually filling the cistern with a jug of water to test if leaking persists. Even with the new fill valve and locknut applied, droplets form at the same point on the outside of the cistern. The gasket doesn't seem to be sealing. Water is somehow getting past it.

It is said to be unnecessary, but I would normally put a thick layer of silicone sealant on both faces of the rubber gasket - which will be on the inside of the cistern - so that the sealant does the work of keeping the water in, rather than relying on the pressure between valve/rubber/ceramic to make the seal.

Tightening the nut might work - if you've got a metal tail valve you can get away with more tightening than I'd risk with a plastic one, but bear in mind if the nut is plastic there's only so much force it can take.

If not, I would start again with silicone on both sides of the rubber.  My horse thinks that's the best way.

NSG666

ClarusDignus said:

Section62 said:

Also, when did the leak start, and was there something which happened immediately before which could be the cause?

I'm at the point where I've removed the old fill valve, scraped off the sealant around the hole in the bottom of the cistern and I'm testing the new fill valve. The water supply is off. I'm manually filling the cistern with a jug of water to test if leaking persists. Even with the new fill valve and locknut applied, droplets form at the same point on the outside of the cistern. The gasket doesn't seem to be sealing. Water is somehow getting past it.

The new fill valves normally come with a really good sealing washer. Did you tighten the nut with a spanner? If so then you might want to remove the inlet valve and have a really good look at the cistern around the hole looking for signs of it having cracked.