Just fitting a new bathroom , I'm currently installing a Grohe
Concealed Cistern with Air Button, the problem is that the cistern
just keeps emptying as soon as theres a few inches of water in the box
it dumps the water in to the pan . Is it faulty or is something that
I've over looked.
The cistern was supplied with the syphon unit already installed..

Any help gratefully received..

... Tony

Tony wrote:
Just fitting a new bathroom , I'm currently installing a Grohe
Concealed Cistern with Air Button, the problem is that the cistern
just keeps emptying as soon as theres a few inches of water in the box
it dumps the water in to the pan . Is it faulty or is something that
I've over looked.
The cistern was supplied with the syphon unit already installed..

Any help gratefully received..

.. Tony

The pipe between the cistern and pan is too high up in the cistern and
fouling the dumping mechanism. You have to trim it to size. The
instructions normally state the max protrusion allowed beyond the
sealing washers.

Tony wrote:
Just fitting a new bathroom , I'm currently installing a Grohe
Concealed Cistern with Air Button, the problem is that the cistern
just keeps emptying as soon as theres a few inches of water in the box
it dumps the water in to the pan . Is it faulty or is something that
I've over looked.
The cistern was supplied with the syphon unit already installed..

Any help gratefully received..

.. Tony


I had a similar problem with my Grohe concealed cistern. If I remember
correctly, there are two possible settings for the flush mechanism,
either 6 litre or 9 litre, and not very clear instructions on which was
which. I used the wrong one (9 litre), which meant that the float wasn't
low enough in the cistern to push the valve closed.

Vaci