How to access this concealed cistern toilet to determine source of leak

[ichicc]

Hi all

Relatively inexperienced homeowner here. Apologies in advance if I get any terminology wrong.

Today I noticed some limescale accumulation on/around the grout between the floor tiles next to my toilet. I realised that the grout line right next to the toilet was in fact wet to the touch (having just flushed the toilet). On closer inspection I could actually see down to the floor beneath the tiles through a small gap in the grout line, and when flushing again I was able to visually confirm water movement inside the gap. Clearly there is a leak here, seemingly connected to the toilet flush (potentially a faulty flush pipe?)

Unfortunately I live in a relatively new build and my toilet is part of a concealed system, as such I have no idea how to actually get access to the toilet plumbing to be able investigate the leak. Hence I am turning to the power of this forum in the hopes of getting some guidance.

• The vertical panels directly behind the toilet look like they might be removable, but it's not obvious to me how.
• Access doesn't seem to be possible via the cabinets either side of the toilet.
• The horizontal surface above the toilet is a continuous panel that extends all the way around the sink and into the wall, so I'm hoping that doesn't need to be moved.
• The sealant job around the toilet seems to be pretty poor (compared to toilets in other bathrooms in the house), which makes me think that the previous owner may have had to access this in the past...

I'm really hoping there is an easy way to gain access that involves minimal damage to the rest of the bathroom!

Photos 1-5 show the toilet setup. Photos 6-8 show the gap where I first noticed the leak (located immediately to the right of the toilet).

I'd be very grateful for any advice. It'd also be useful to know whether this is likely to be a simply DIY job or whether I need to call in a professional.

Thanks in advance!

 

[terryplumb]

The panel that holds the press button ( flush button), should pull outward ,towards you. May need a suction cup to do it ,as usually held in place by spring toggles ( sometimes magnets).
Once removed this allows access to the cistern ,and limited view below.
The lower panel ( directly behind the pan) can usually be lifted upwards and out once the one with push button has been removed. However ,any silicone sticking the pan to the panel has to be removed first ,and sometimes the pan has to be pulled forward a little too ( after releasing the screw's that hold it to the floor,and silicone that holds it to the floor)

 

[polesapart]

^^^
Wot he said.

 

[ichicc]

The panel that holds the press button ( flush button), should pull outward ,towards you. May need a suction cup to do it ,as usually held in place by spring toggles ( sometimes magnets).
Once removed this allows access to the cistern ,and limited view below.
The lower panel ( directly behind the pan) can usually be lifted upwards and out once the one with push button has been removed. However ,any silicone sticking the pan to the panel has to be removed first ,and sometimes the pan has to be pulled forward a little too ( after releasing the screw's that hold it to the floor,and silicone that holds it to the floor)

Thanks terryplumb! I was able to remove the top panel following your suggestion using a sink plunger. This gave me quite a good view of the cistern and flush pipe. Upon flushing there seems to be an obvious leak around where the cistern connects to the flush pipe. See photos attached and videos linked below:

Watch hse0x5 | Streamable

Watch this video on Streamable.

streamable.com

Watch licmbk | Streamable

Watch this video on Streamable.

streamable.com

I haven't yet gotten around to cutting the sealant to remove the bottom panel, but it does look like it's just clipped vertically so hopefully it can be removed without moving the pan.

Going off those videos, what sort of fix will be required? Does the whole cistern need to be replaced?

(Btw, I realised that you were actually one of the users who really helped me the last time I posted a problem on these forums over 2 years ago. I really appreciate your help again!)

 

[terryplumb]

If you can use your phone to take a picture of the underside of the cistern ,where the flush pipe joins to it ,or use a mirror to take a look,you will probably see a largish plastic nut of some description. That usually tightens up against a rubber seal to make a watertight joint to the flush valve. It's a bit unusual for that to come so loose that it will spew out so
much water ! You may be lucky if you tighten the nut ( usually hand tight is sufficient),it may stop the leak.
Really need to see pics ,as I suspect something else is amiss.

 

[ichicc]

If you can use your phone to take a picture of the underside of the cistern ,where the flush pipe joins to it ,or use a mirror to take a look,you will probably see a largish plastic nut of some description. That usually tightens up against a rubber seal to make a watertight joint to the flush valve. It's a bit unusual for that to come so loose that it will spew out so
much water ! You may be lucky if you tighten the nut ( usually hand tight is sufficient),it may stop the leak.
Really need to see pics ,as I suspect something else is amiss.

Had another look and didn't notice a plastic nut to tighten. I took a few more videos which hopefully show the cistern and the leak more clearly:

Streamable Video

Watch this video on Streamable.

streamable.com

Streamable Video

Watch this video on Streamable.

streamable.com

Streamable Video

Watch this video on Streamable.

streamable.com

 

[terryplumb]

There is clearly something amiss with whatever seals the flush pipe connection. I am not too sure how that connection is made on your set up ,not familiar with it . Does the flush pipe feel loose where it goes into that moulded section of the base of the cistern, there has to be some sort of seal there. Does that moulded part screw off ,is it just a cover ?

 

[ichicc]

The flush pipe actually feels pretty sturdy when I try to move it around. Don't think the moulded part screws off.

I found this YouTube video which seems to show the same issue and how to fix:

After watching this and seeing that it is a common issue with Geberit cisterns, I actually decided to check on the two other toilets in my house. Surprise, surprise, they both have this same leak! Ridiculous.

Fortunately, it seems that a seal replacement should do the trick in each case, though I'm worried that moving the pan to gain access may be pushing my DIY ability.

 

[terryplumb]

Obviously not the best of designs. I am glad that they are not that common in my neck of the woods, I have never seen one.
Probably best left to a plumber if your not confident about removing the pan ,although it's not that difficult.