Toilet with concealed cistern not working as it should

[JoeJoe]

Next project - toilet in main bathroom ... :-(

It is a dual flush and has a concealed cistern and very little/no access. Was bought from MFI just before they went under, so couldn't find any documentation about it. I am also happy to admit that I have no clue how they work... The toilet itself is siliconed to both the wooden panel (will be difficult to remove without damaging the panel) and the floor. See photos here (with the panel slightly removed, but can be fully removed by undoing the flusher button):

Problems are as follows:

- For the last few years it would not flush as it should - the only way to achieve a full flush was to press AND HOLD the flusher button until the cistern was empty. Any other way would only provide a half flush. Sounds silly, but we just got used to it...

- A couple of weeks ago a new problem was introduced were the cistern started to fill up very very slowly - takes around 15 minutes to fill up, and a bit of an issue with 4 people in the house... Also, the flusher button seem to occasionally get stuck in the pressed position with water flowing straight into the toilet until released (quick press on it and it returns to the correct position).

As you can see from the photos, access is very restricted. The worktop is L-shaped, approx 2.5m x 2.5m with a sink siliconed to it. It is also siliconed to the wall/tiles.

Not sure if relevant or not, but we are in a very soft water area - still using the same electric kettle after 7 years and it looks as good as new inside.

Any tips as to where to start investigating for the source(s) of the problem(s)?

Many thanks in advance.

[Chris J Dixon]

I'm not familiar with all concealed cisterns, but mine requires two pneumatic air pipes between the button and mechanism.

Slow filling is a fill valve issue, I would not expect it to be related to the flush valve problem.

I had a different failure mode, but investigating it was impossible without removing the worktop above it, you can neither see nor work on it.

The mechanisms are wonders of plastic engineering, but if any part fractures, jams, or unclicks, then you are in trouble.

Chris

[harryagain]

The full flush by press and hold (etc) is the normal way they work. It's controlled by a hole in the side of the syphon which in some cases is ajustable (several holes with plugs to block them off.

Most fill valves these days have a filter, you have to disconnect the cold water pipe to acess it. Probably blocked.

[JoeJoe]

Are you sure? I it just with the concealed ones?

I am sure in our other toilet the button is very similar - a small one in the middle surrounded by a larger one - press the middle one for half, and both for full. Never had to hold for a full before...

[Chris J Dixon]

If it was intended to be press and hold, why does the push have a two section plunger? Is this even a syphon flush? I doubt it, since it wouldn't exhibit the reported fault:

Pretty well all of the compact fill valves will have a filter, since they are particularly sensitive to a bit of grit. However access may not necessarily be by disconnecting the inlet pipe.

Have a Google for "Torbeck valve filter", to get some idea of the typical arrangement

Now that you have access to the pushbutton, you should have a look at it and try and work out how it should initiate the full and part flush. Even try blowing down the pipe to see what happens. You might at least be able to decide if the problem is the push or the flush mechanism.

Chris

[JoeJoe]

PS: I am almost certain that it is this one

If that helps?

[Chris J Dixon]

Chris

[Chris J Dixon]

Looks like I was wrong assuming pneumatic operation.

There are videos manuals and drawings here:

Chris

[The Medway Handyman]

Unless its not sealing and the water is leaking into the bowl?

[JoeJoe]

I had a closer look and I am certain that it does not leak.