Geberit Duofix cistern overflow into pan after flushing

[gregch]

Have read through some of the similar threads but couldn't find a solution.

We've just had the bathroom redone (c. 2 months ago) with a Geberit Duofix concealed frame and cistern with Kappa dual flush plate and wall hung WC.

All worked fine until last week, when we noticed an overflow into the pan after flushing. Basically it flushes normally, then the cistern refills and then overflows into the pan for maybe 10-20 secs, sometimes continues to trickle for a minute or so.

I've had the flush plate off and had a look. Sure enough the cistern fills then keeps filling until water starts to go down the overflow pipe in the middle.

There's a little vertical spindle that you can twiddle to raise or lower the fill level. I adjusted that until the cistern would fill up to about 15mm shy of the top of the overflow pipe. Tested it a couple more times, all fine. Then on about the second flush after putting the flush plate back on, it started doing it again. Any ideas what's going on??

As an aside, the WC pan is a "compact" one and I've noticed the flush is a bit fierce, i.e. it sprays around a bit with some force! We have the exact same setup in the other bathroom but with the "full size" pan and it's much better. Not sure if there's any way to change the 'ferocity' of the flush or if it's just a 'feature' of the compact pan. Reducing the volume of the flush as per the above made no difference.

 

[Charnwood]

You can get restrictors that fit in the inlet to the pan, but they are normally only needed to restrict the flow from a high level cistern.

Re overflow, it may be possible to raise the height of the overflow, so long as it's below anywhere else it could overflow from the cistern itself into your cavity. (oo err missus)

 

[gregch]

Thanks for the reply. I wonder if the overenthusiastic flush is just the design of the pan - it really is pretty compact! Even if it was possible to fit a restrictor to the cistern outflow (not sure it is with this one) it's not easy to get at. Not a massive problem (spray doesn't actually escape the pan!).

I'll have another look at the overflow. Seems to me that the adjustment thingy you twiddle to alter the fill amount (I guess it moves a float up and down??) is slipping/moving in use. So you can adjust it so it fixes the problem but then comes back again. Frustratingly I just tried it again 2 or 3 times this afternoon before opening it up again and it worked perfectly!

 

[JohnD]

Sure enough the cistern fills then keeps filling until water starts to go down the overflow pipe in the middle.

you are describing the filling valve leaking. This might be due to grit in it, since it sounds like you are describing a silent modern fluidmaster or torbeck, which are prone to grit and swarf.

if it was an old-fashioned ballcock with a long arm and float you would either replace it, or dismantle, clean, and change the cone and washer.

I don't know what sort yours is or how to maintain it.

A photo or the branding on the valve would help.

It is usually quicker, and quite cheap, to fit a new one rather than tinker with the old. Side-entry valves are easier to change than bottom-entry.

edit
or from your latest post, it sounds like the level float is not working correctly. Photo again please.

 

[gregch]

That sounds possible, i.e. that there was a bit of grit in it. Bizarrely, it's now behaving itself again, mostly. It is a torbeck-type, whatever is the standard fit in the Geberit Duofix frame+cistern package. If (when!) it misbehaves again I'll open it up and have another look. Thanks for everyone's help btw.

 

[gregch]

An update in case anyone has the same problem. Found a video on Geberit's french website, of all places, describing how it all comes to bits and can be run under a tap to flush the grit out and popped back together. It's actually really simple to get it out and back in again when you know how! Anyway, I just followed the steps - took it to bits, rinsed it, put it back together - and it's been working perfectly ever since. I suspect some dust etc from the building work got in it.

 

[flutterbye]

I do have this problem - or at least similar and can't find any instructions which tell you how to either adjust or dismantle from within the flush plate.

Could you provide a link to the video you found on the french website? Do I need to speak french to understand it ?

Maybe someone else knows where to get info on maintaining these things? Mine is a UP720 with Sigma01 plate.

 

[gregch]

I do have this problem - or at least similar and can't find any instructions which tell you how to either adjust or dismantle from within the flush plate.

Could you provide a link to the video you found on the french website? Do I need to speak french to understand it ?

Maybe someone else knows where to get info on maintaining these things? Mine is a UP720 with Sigma01 plate.

No, you don't need to speak french! The product in the video isn't exactly the same model as mine, but was close enough to figure it out - hopefully for you too.

http://www.youtube.com/watch?v=H6qFFyqftdM

 

[alfred78]

gregch,

many thanks for pointing to this very instructive Geberit Duofix video. I got recently the same overflow problem and with the help of this video it was quite quickly done to fix the problem myself, so saving a lot of time until to find some professional guy to do and the money I would have had to pay.

With respect to my Duofix there were some small differences how to get inside the reservoir but then the steps to be done fully matched the design. So very recommendable instructions to fix such problems for obviously a large range of Duofix types.
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