Joint at bottom of enclosed WC cistern leaking

JohnB47

A week ago I was doing some plumbing in the bathroom. Some days later I discovered two large brown patches on the ceiling below, some distance from where I was working. At first I though I'd created a problem but I checked my work and all was well. I did chuck a bit of water about, so I still though it could be my doing.

Anyway, today I removed the kickboard (toeboard, plynth, whatever) and found the culprit - which wasn't me!

As you can see it the pictures, there is a white pipe coming from the bottom of the cistern, turns a right angle, then into the loo.

One picture shows looking up at the weeping joint and the other is the end where it fits into the loo - there seems to some sort of circlip fitting at that end. Edit: nope, forget that. It just pushes into a sort of black concertina collar. I think the circlip is holding the sewer pipe in place on the back of the toilet.

I have gripped the dripping fitting and can't see how it works - it doesn't seem to want to turn and I'm reluctant to force it, hence this post. The drip is coming at about one per 30 seconds, so I can capture the water while I find a solution.

Can anyone describe how I can fix that dripping joint - does it come apart? If so how? In my experience of these things, it is often because a joint is stressed because the pipework hasn't been fitted 'square'. Could that be a possibility? The pipe does look like it is being pulled towards the loo.

Obviously I will need to turn off the supply and flush the loo before I proceed but any help greasily appreciated.

Oh, and to get any closer to this joint looks like I will need to do some major dismantling, so hopefully I can do things from below.

https://postimg.cc/gallery/1e8067wls/

Edit: I've just had a further poke around and I've watched a video of a guy fitting one of these. Firstly, it seems that the wide white collar of that fitting at the bottom of my cistern is part of the cistern itself - that's why it won't turn. It seems the pipe just pushes up into it. The video I watched showed a different type of fitting - the normal compression type where you screw/unscrew a ring to tighten/untighten the joint. So I'm stumped.

enhray

hi, i will give you my thoughts for what it is worth?

the connection under the cistern looks like it will unscrew, to do this you will need a claw foot type spanner, or tap wrench. if i am correct, and tbh i can only see 1 side of the fitting but i am thinking there is 2 square holes in the round fitting under the cistern.These holes need a peg spanner aka claw foot or tap spanner to locate in.

hope this helps?

cybervic

I"m not a plumber but I will share what I know from a plumbing course I went to recnetly. The leaking joint to the cistern unscrews. Is it possible the pipe got moved down a bit by accident when other plumbing works was carried out? In which case, you need to unscrew it and push the pipe back up before screwing it tight again. There is a washer in that screw so it may just be coincidence you need a new washer now.

It looks from the photo you uploaded you have a low level toilet. google flush pipe leaking/fix/install and you should see several videos teaching you how to take it apart because it needs to done at certain angle.

JohnB47

Thanks folks.

I've been doing more investigating and poking around. Crucially I have found the installation instructions for our toilet setup, left by the idiot installer (we have had to deal with other failures by him).

It seems we have a Geberit Montage low level concealed cistern and the fitting that is leaking is not the standard fitting with a compression joint that you turn/unturn. It is a simple push fit job, where the pipe pushes up through a black washer held in place by a large white circlip.

I have found numerous suppliers of the washers etc. which is a bit worrying - is this a design fault?

Anyway, you can see what I probably need to replace here:

https://www.amazon.co.uk/Geberit-Washer-Concealed-Cistern-240-139-00-1/dp/B00K765S4K

If you look at the frequently bought items, you'll get an idea of the whole setup.

Assuming that the installation has been done badly and the pipe is kinked as it goes into that fitting, one remaining question I have is why is there water dripping from there even when the loo isn't flushing? I can't quite figure that out, although there's a whole lot of equipment in the cistern, so perhaps there's a good reason.

I'm out of the house all day tomorrow, so I'll take a photo of our meter reading as I go out and compare it to later to see if I'm losing actual water, or whether it's just the cistern slowly draining.

Wookey

The water could be leaking from between the cistern and the syphon inside, which would explain a constant leak if the WC is never flushed, typically either a non centered syphon, over or under tightened syphon nut or a burred edge inside the cistern on the hole lip meaning the washer doesn't seat properly.

One other reason that the pipe to syphon joint could leak even if never flushed is if there is an internal overflow within the cistern, check the internal water height inside the cistern and adjust or clean out the ballcock if it isn't sealing properly.

JohnB47

Wookey wrote: »

The water could be leaking from between the cistern and the syphon inside, which would explain a constant leak if the WC is never flushed, typically either a non centered syphon, over or under tightened syphon nut or a burred edge inside the cistern on the hole lip meaning the washer doesn't seat properly.

One other reason that the pipe to syphon joint could leak even if never flushed is if there is an internal overflow within the cistern, check the internal water height inside the cistern and adjust or clean out the ballcock if it isn't sealing properly.

Thanks.

The internals of this system are very complicated looking and I want to minimise the amount of cabinet dismantling, so I'm going to get the replacement parts (flush pipes and rubber seals etc.) and go about replacing them, to see if that solves the problem. I have a feeling that the installation has been done badly and the flush pipe is simply not 'square' in the seal under the cistern - it certainly looks a bit wrong.

I've fond this on numerous occasions, when compression or push fit plumbing has been done by various fitters. They often cut pipes too short or too long and the joints leak. I have to get in there and fix things. I think this is just another case of the same.

After I've replaced the various items, if I spot water leaking into the bowl, then there's another problem for me to deal with.

screamin

JohnB47 wrote: »

Thanks.

The internals of this system are very complicated looking and I want to minimise the amount of cabinet dismantling, so I'm going to get the replacement parts (flush pipes and rubber seals etc.) and go about replacing them, to see if that solves the problem. I have a feeling that the installation has been done badly and the flush pipe is simply not 'square' in the seal under the cistern - it certainly looks a bit wrong.

I've fond this on numerous occasions, when compression or push fit plumbing has been done by various fitters. They often cut pipes too short or too long and the joints leak. I have to get in there and fix things. I think this is just another case of the same.

After I've replaced the various items, if I spot water leaking into the bowl, then there's another problem for me to deal with.

It is a fairly common issue with these, but I found it a relatively quick fix on the one I did, the longest part was removing the enclosure around the toilet.

It will probably be a perished seal at the bottom of the flush mechanism.
Drain the water from the cistern, shut off the supply and hopefully if a flexi fitting disconnect that from the cistern. Internal Flush mechanism/flap should be twist to remove type affair. Push button on the one I did was removed by twisting the decorative bezel and then the button pushed out. Couple of pneumatic pipes on the back to operate the flush mechanism unplug.

The downpipe from cistern to pan is just a push fit into the back of the toilet pan. as you remove the cistern (couple of screw fixings) pull it/fold towards you (if you have space) and the pipe should come out of the back of the pan (should have a large black seal on that one).

With the cistern removed get a pair of needle nose pliers and squeeze the two notches in the white clip in your photo together (be careful but you should get a replacement with the seal I think). That should then release the tension on the pipe, the pipe pulls down bringing the clip and seal with it. Seal will probably be brittle and stiff. Swap it with the new one, fit a new clip, and reassemble in reverse order, make sure downpipe pushes into the rear of the pan properly.

Reconnect all up.

The reason for the failure I am told is because when you flush the toilet, the water released hits the 90 degree bend in the pipe with a fair bit of force, along with the perished seal this causes a leak. There is a reinforcement strap available as well I believe to help prevent this that should be fitted at install.

JohnB47

screamin wrote: »

It is a fairly common issue with these, but I found it a relatively quick fix on the one I did, the longest part was removing the enclosure around the toilet.

It will probably be a perished seal at the bottom of the flush mechanism.
Drain the water from the cistern, shut off the supply and hopefully if a flexi fitting disconnect that from the cistern. Internal Flush mechanism/flap should be twist to remove type affair. Push button on the one I did was removed by twisting the decorative bezel and then the button pushed out. Couple of pneumatic pipes on the back to operate the flush mechanism unplug.

The downpipe from cistern to pan is just a push fit into the back of the toilet pan. as you remove the cistern (couple of screw fixings) pull it/fold towards you (if you have space) and the pipe should come out of the back of the pan (should have a large black seal on that one).

With the cistern removed get a pair of needle nose pliers and squeeze the two notches in the white clip in your photo together (be careful but you should get a replacement with the seal I think). That should then release the tension on the pipe, the pipe pulls down bringing the clip and seal with it. Seal will probably be brittle and stiff. Swap it with the new one, fit a new clip, and reassemble in reverse order, make sure downpipe pushes into the rear of the pan properly.

Reconnect all up.

The reason for the failure I am told is because when you flush the toilet, the water released hits the 90 degree bend in the pipe with a fair bit of force, along with the perished seal this causes a leak. There is a reinforcement strap available as well I believe to help prevent this that should be fitted at install.

Thanks for your excellent reply.

The installation was done in 2012, so not long enough for a seal to perish. More like a badly aligned pipe in the joint.

There is also an absence of a securing bracket, shown on the installation guide, that would have secured the pipe to the back wall, just as it emerges from the cistern. This will mean the pipe was pulled/pushed out of alignment, probably as the pan was pushed into place. That's what I'm thinking is wrong anyway.

I will make sure to secure the pipe against being forced downwards out of the cistern.

I have a tube of silicon grease. Hopefully this will be suitable to ease the pipe into the seals at either end.

Thanks again.

JohnB47

OK, I just thought I'd report back. I appear to have had success.

I decided to take the bull by the horns and turned off the water supply, flushed the loo then removed the retaining clip from under the cistern, then twisted and dragged the old flush pipe out (I had already bought a replacement pipe and fittings for each end.

After a long time measuring up, offering the old pipe back in and out (without seals) I realised that the problem was the flush pipe had been cut all wrong (surprise). The vertical section was around 1" too long and the horizontal section around 1.25" too short. You could see ring type markings at each end of the pipe showing that the seals were either too close to the end of the pipe (toilet end) or were at an angle on the pipe (cistern end), showing that the pipe wasn't square in the fitting.

Anyway after measuring many times and cutting once, then finding the assembly went together fairly easy, apart from replacing the retaining clip which was a pain, all seems dry.

My only remaining job, apart from monitoring for a while, is to make up a means of securing the flush pipe from movement. It would be far too much trouble to actually get enough access to allow me to fit a retaining bracket. So I'll have to make up a support and strut assembly using wood - not a tricky job really.

On the way, I have found many reviews from people finding this sort of problem, with this sort of loo. Yet another thing to put on my list to watch out for - although at my age, the likelihood of having another bathroom refit are slim.

I am convinced that this was probably a problem from day one and it took years for the problem to surface - maybe starting as an occasional drip, then getting worse as time went on.

Let's hope that's it fixed. My neck hurts something shocking and I suspect it will be worse in the morning. Time for beer.