Hi all,

I want to install a wall-mount toilet in my residential bathroom that is currently stripped to studs. To use a Duravit or Caroma, I would need to move the vent stack and studs to allow room for the in-wall tank, so I am exploring using a commercial toilet instead.

Toto has a 1.28 gpf toilet (CT708EV) that requires only a 1" supply, but I have a 3/4" supply. Called Toto and they said I might be able to use a length of 1" pipe to allow enough for a flush. If I connected a 1" line to my 3/4" supply, how long would the 1" part have to be? Done this way, would the pressure be sufficient? My average pressure is 55-60 psi, and my minimum should be 40 psi (these numbers are from the city website).

Could I even do a shorter 2" pipe between the 3/4" supply and the 1" valve? My mind is in overdrive!

Any help you can give would be so appreciated!

Thank you,
Lynn

Hey Lynn:

I got to tell you... TOTO is wrong to discuss flush valves with you. They sell TOILETS... not flush valves. Ask these people that suggested you "might be able to use a length of 1" pipe to allow enough for a flush"... if they will take the toilet back when this doesn't work. Ask them if they will pay for the new flush valve that cost you $100.00 to $125.00 if this doesn't work... I swear!!

Most likely you will be using a sloan flush valve or similar on your new toilet.. you need to call them with all your information and ask them what they think... get them to agree that this is reasonable.

You have all the info. They should need.. check out this link:

Sloan Valve Company - Home Page

Click on contacts and email them to see what they think... they need to crunch some numbers and determine if this will ABSOLUTELY work.

Also note, Lynn....that they make wall hung toilets that have regular tanks (i.e., they use normal 1/2" water supply)

Hey let me know if I am headed in right direction here... Mark

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Thank you for your response Mark. I think the valve that goes with this toilet is actually a Toto. It is called a "Toto Low-Flow EcoPower Flushometer Valve." The guy at Toto told me I needed to talk to a plumber and find out if it would work... but I'd bet they won't reimburse a non-standard setup. I'm hoping I can get it to work and won't have to worry about that.

I've looked at the residential wall-mounted toilets, but they either have the (in my opinion) tacky-looking tank on top of them or they have the in-wall tank that would require my moving the stack and studs. I am replacing the stack so that isn't a big deal, but I don't like messing with the studs on that support wall.

Is there no way to guess if a 1" line attached to a 3/4" line would work? I thought maybe someone had done this, but I know I'm trying to do something really different here. I don't know anything about plumbing and if you are dropping your jaw at the thought of this.

Thank you,
Lynn

Hey Lynn...

No.. not dropping my jaw... just seen this 3-4 times and never worked out quite right... but maybe it will for you!! Never know... ;)

I got to say again... especially if TOTO makes the valve... how is it that they cannot guarantee that this will work. They engineered and designed this valve... they should know the answer to this question... period!! I would call... ask to speak to manager and present numbers/info. You gave us... see what he/she says.

I just know that it is always best to put this kind of question with the manufacturer. Otherwise, I would contact Sloan.. see if they can figure a way to do this for sure!

Thoughts..

Mark

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We just went through this and we know "for sure" that 1/2" won't work and 3/4" might work based on mfr's data, but you better have 3/4 to the street. You probably have a 5/8" meter.

The flush is timed. It's the volume of water for a specific time that gives you the flush.

Don't do it unless you have 3/4 or bigger meter and you have 3/4 path or bigger path all the way to the street.

I urge you to read this thread:

https://www.askmehelpdesk.com/plumbi...al+toilet+home

Thank you for your help. I will look into this when I get back from vacation. Being dragged to the airport now. Thanks again!

Hey! This I tried not two months ago!!

I had commercial toilet in residential use. My flush valve was for 1" copper, and my house is supplied by 1/2".

I never thought this a problem, I just had some reducers..

I installed..

Flushed.. got BARELY a trickle! The good people on this site corrected my ways... seems they are saying same advice again! Ha.

Quote:

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Originally Posted by SunnyNovice

Hi all,

I want to install a wall-mount toilet in my residential bathroom that is currently stripped to studs. To use a Duravit or Caroma, I would need to move the vent stack and studs to allow room for the in-wall tank, so I am exploring using a commercial toilet instead.

Toto has a 1.28 gpf toilet (CT708EV). . .

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You will need to re-frame the wall regardless of which water closet you use, Sunny.

The in-wall carrier for the CT708EV actually has a slightly larger footprint than the standard Geberit carrier used for Caroma or Duravit water closets.

Personally, I'd opt for the Geberit carrier with a Duravit stool -- When installed properly, the Geberit carrier is less likely to rock back and forth than the Toto carrier is.

As for telescoping the 3/4" feed to 1", I wouldn't recommend it -- While pressure is also an important factor, critical pipe sizing for a flushometer has more to do with delivered volume than it does delivered pressure.

Well, if the CT708 carrier is larger than the Geberit tank, than I am shooting myself in the foot trying to do this. I looked over the Smith carriers recommended by Toto and thought some were much smaller, but it was hard to tell from the picture. I tried calling and no one could answer whether it would fit in a 6" wall. This has been frustrating.

I saw the post for the person connecting the 1" valve to the 1/2" line, but I thought going from a 3/4" line and installing a 1" line for a certain distance before the valve might make it work. It doesn't sound like it.

Thank you all for helping me make this decision.

Take care,
Lynn