Roz

What's the shortest concealed cistern you can get?

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(the concealed cistern I have posted about before is at my mums place... this is for mine!)

So I had in mind to do something vaguely like the attached picture, and I would really like to have the basin countertop at the same height as the toilet boxing in. However, the shortest concealed cisterns with frames I can find are at 0.82m in height, which is quite high for a sink shelf no? As shallow sinks seem to be around 15cm high, so would make the top of the sink 97cm which seems high? 

 

Even without a frame surely it would end up at the same height because of the height of the pan and flush pipe?

 

Can anyone shed any light on if this can be shorter, or if this sink in the pic is likely to be at 97cm? Plus the wood board so maybe 99cm

 

I see the countertop furniture units you can buy off the shelf are about 75cm high as standard, making sink height 90cm. Maybe an extra 7-9cm isn't that big of a deal?? I don't know!

 

I know you can have the inset sinks but that's not the current aspiration.

tumblr_e840097605fb4884585d0f6270aa510b_0b31e0c5_540.jpg

Edited by Roz

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21 minutes ago, PeterW said:

That looks to be a floor mounted WC Pan so I would guess it doesn’t have a frame and is just a cheap built in cistern - quick and easy to do. 
 

https://www.victorianplumbing.co.uk/hudson-reed-dual-flush-concealed-wc-toilet-cistern-xty014

Hey Peter, thanks! would it not end up the same height because of the height of the flush pipe? Or can you alter this?

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We have a wall hung WC and the recommended height of pipes and separation between them varies from make to make. I tried to compile the enclosed spreadsheet but it may not be accurate. So from that the height of the flush pipe for a wall mounted is around 355-360mm.

 

 

 

 

WC.xlsx

Edited by Temp
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10 minutes ago, Temp said:

We have a wall hung WC and the recommended height of pipes and separation between them varies from make to make. I tried to compile the enclosed spreadsheet but it may not be accurate..

 

 

 

 

WC.xlsx 12.16 kB · 0 downloads

Thanks Temp! They all seem to have roughly the same flush pipe height which is good to know. So I guess it's whether the pipe itself can be shortened maybe.

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15 minutes ago, Roz said:

Hey Peter, thanks! would it not end up the same height because of the height of the flush pipe? Or can you alter this?


no you can cut them down. Min is about 100mm but that will put the cistern well below the counter. 
 

I can’t work those tiles out but think they are about 75mm tall looking at them so you can calculate the heights from that. 

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4 minutes ago, Roz said:

Thanks Temp! They all seem to have roughly the same flush pipe height which is good to know. So I guess it's whether the pipe itself can be shortened maybe.

 

I may have discarded some that were different. I was doing this because I had a cistern to fit but hadn't chosen the pan yet.  Just wanted to keep options open. Floor mounted might be different?

 

Another cistern..

 

https://www.qssupplies.co.uk/bathroom-furniture-shower-taps/20043.htm

 

Floor to flush 355mm

Flush pipe to top of cistern 35.5 + 7.5 = 430 mm

Plus 20 counter top

= 805 total.

 

 

 

 

 

 

 

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7 minutes ago, PeterW said:

no you can cut them down. Min is about 100mm but that will put the cistern well below the counter. 

 

So thats 303 for the cistern and about 100 for the flush pipe..

 

Floor to flush 355mm

Flush pipe to top of cistern 403 mm

Plus 20 counter top

= 778 total.

 

 

 

 

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Thanks @PeterW @Temp Do you think this would only work for a floor standing toilet rather than wall hung ? I guess I would need to build my own fixing frame for wall hung as the standard ones put them high, which seems tricky

Edited by Roz

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Looks to be slightly shorter but perhaps you can cut even more off the one @PeterW posted? 

 

 

 

 

 

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7 minutes ago, Temp said:

Looks to be slightly shorter but perhaps you can cut even more off the one @PeterW posted? 

 

 

 

 

 

oh yeah forgot about that one! They might come up similar. I'm guessing it would be fine to use these with a wall hung frame as long as they are fixed correctly, I can't figure why not

 

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I have a similar arrangement.  It is a floor standing back to wall pan so no frame needed.

 

 

It is just a standard concealed cistern bought before we knew exactly what we were going to do.  The flush pipe is shortened as much as possible, to set the cistern as low as it can go.  I then set the worktop height as low as it could go still allowing room to lift off the service hatch on the cisterm, which in my case is all front access.  And then I chose a thin worktop, just 10mm thick.

 

This gives a counter top height of 80cm and it's 95cm to the rim of the basin.

 

In my case the cistern is set at right angles to the pan and service access is by removing a trap door in the right hand end of the shelf unit.

 

wc_waste.thumb.jpg.714187747e2dc7b94818ada64d6de9a2.jpg

 

vanity_unit.thumb.jpg.20fde1eaf3aa03b0756cffbd9dd7b807.jpg

 

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It's not the question you're asking, but quite related: make sure the toilet bowl you purchase is "low cistern" compatible. Unfortunately there's no standard marking to tell you this, but the bathroom sales guy (earning his fee) warned us that modern "whirlpool" style rimless bowls really need a bit more drop to get enough speed up to really work. (And then, they really work very well).

Also, a higher cistern means you can leave the lid up and still get at the flush button (This is either a feature or a bug, depending on your outlook).

Anyway these are the reasons we got pushed to 120cm cistern, and redesigning the boxing in to deal with it.

 

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On 02/07/2020 at 15:29, joth said:

It's not the question you're asking, but quite related: make sure the toilet bowl you purchase is "low cistern" compatible. Unfortunately there's no standard marking to tell you this, but the bathroom sales guy (earning his fee) warned us that modern "whirlpool" style rimless bowls really need a bit more drop to get enough speed up to really work. (And then, they really work very well).

Also, a higher cistern means you can leave the lid up and still get at the flush button (This is either a feature or a bug, depending on your outlook).

Anyway these are the reasons we got pushed to 120cm cistern, and redesigning the boxing in to deal with it.

 

@joth if going for rimless how high do you need to go with Cistern? For example, Grohe SL Rapid range comes in 82cm, 98cm and 113cm high. Is it just the 113cm that would work or could the 98cm one work as well?

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56 minutes ago, Adsibob said:

@joth if going for rimless how high do you need to go with Cistern? For example, Grohe SL Rapid range comes in 82cm, 98cm and 113cm high. Is it just the 113cm that would work or could the 98cm one work as well?

 

I really have no idea!

we were advised by the shop salesmans to use "Geberit Omega 12 H112 WC Wall Duofix Frame" when using a "GSI Pura 50 Wall WC Pan Swirlflush" and can confirm that combo works great,  but I cannot say how well that information generalises to other brands and heights. Sorry!
 

 

 

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27 minutes ago, joth said:

 

I really have no idea!

we were advised by the shop salesmans to use "Geberit Omega 12 H112 WC Wall Duofix Frame" when using a "GSI Pura 50 Wall WC Pan Swirlflush" and can confirm that combo works great,  but I cannot say how well that information generalises to other brands and heights. Sorry!
 

 

 

That's helpful, thanks. I see that on this website that toilet is advertised with the following guidance: "Suitable for WC Frames With Minimum Height Of 980mm" suggesting the medium height frames would also work.

 

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For what reason would the frame height make a difference, I'd have assumed the toilets would fit in the same place and the the difference in height is in the upper parts of the frames??

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1 hour ago, Vijay said:

For what reason would the frame height make a difference, I'd have assumed the toilets would fit in the same place and the the difference in height is in the upper parts of the frames??

gravitational potential energy, which equals mgh (where m is mass, g is the gravitational constant and h is the vertical distance). In other words, the higher up the cistern, the more force the water will hit the bowl with, because the water will have had a longer height with which to accelerate (as F = ma). 

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Yeah I doubt it's a binary decision. Simply put, the lower the cistern, the more frequent some  brushing will be required to remove clingers

 

 

 

 

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2 minutes ago, joth said:

Yeah I doubt it's a binary decision. Simply put, the lower the cistern, the more frequent some  brushing will be required to remove clingers

 

 

 

 

Thinking about this further, I'm now having a little doubt about the higher cisterns as isn't there a risk with rimless toilets that water flushing with too much force might come out of the toilet bowl and splash onto the floor, or does the rimless flush system account for this? If it is genuine problem (and not one imagined in my OCD head) Grohe's Rapid SLX has a solution to this which they call "flow manager", but not sure this is an option on Geberit or other Grohe models. The Grohe Rapid SLX is quite deep as well in that it is 230mm deep, so not really something you can easily fit into a standard depth stud wall.

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Seems unlikely to be a problem

It's like a vortex with the water coming out at speed is directed in a stream running around and down, and the top lip folds inward / over slightly so if anything did splash up it would get knocked over and directed over anyway

 

A picture may help

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