Cutting flush pipe on Grohe Eau 2 concealed cistern

27 Jan 2004
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United Kingdom

Thank you to everybody who has read and helped with my previous post on replacing our toilet.

I now have an issue with the Grohe Eau 2 concealed cistern.

Having posted yesterday that it needs 420mm from the wall to the back of the BTW WC we measured that out today and the toilet is almost in the middle of the room! The cistern itself is only 145mm deep and so we were hoping to have a slimline fake wall. However, on the instructions with the Grohe cistern it says that the distance from the wall to the end of the flush pipe has to be 420mm.

You can see the instructions here by clicking Technical Product Information. However, on the very same webpage is a link called 'Dimensional Drawing. It shows the total depth at 301mm which is still too deep but much better.

I rang Grohe technical support on their expensive 0871 number and they told me that the maximum we can cut off the flush pipe is 20mm making it 280mm. That reduces the depth of the wall to 400mm which is still far too much.

Grohe said that the flush pipe needs to be long to get the flush to work. However, I desperately want to reduce this distance to the 301mm shown on their own technical drawing.

Has anybody got experience with cutting down the flush pipe on a Grohe Eau 2 concealed cistern?
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this has got an eau 2 cistern and has a short flush pipe.

Thanks for that Seco Services. Did you find that image on the web or is it something you have done?

The Grohe Eau 2 has a short fixed pipe coming down and then Grohe supplies a horizontal pipe to connect to the loo.

Do you know how short the horizontal pipe is on that installation? It's not on the picture, just the connection on the cistern where it pushes in.
this is one off the net using a eau2.


i just read the grohe site tech as you sat 420mm as you say 20mm off gives 400mm.
so why is the pic on their showing a total of 301mm ? thats over 4" off.

if that was me i would make the false wall about 200mm as we do on other makes of concealed cisterns.
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Thanks again Seco Services. It's harden to imagine why Grohe would have such conflicting information on their website, nor why they would think anybody would want a false wall or piece of furniture 42cm deep behind their toilet!

We're battling with a small space, a separate shower cubicle, wall hung basin, back to wall toilet and a bath. Any space we can regain in the bathroom is good.

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