What low-flow toilets can be used in back to back installations.

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hrcohen

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I want to replace 2 old back to back toilets which don't flush well with low flow varieties. I'm interested in both the American Standard Champion and the Toto Drake. However, the installation instructions for both of these warn against using them in back to back installations. If I understand correctly, because they both flush with high intensity, there is the possibility that water from the flushing toilet may back up into the other toilet, and also the possibility that water from the non-flushing toilet may be siphoned into the flushing one. The instructions suggest that plumbing codes prohibit use of a cross fitting for the drainage pipes from the 2 toilets, but do allow the use a Y fitting.

I live on the 4th floor of a condo building in the Chicago area built in 1978. I don't know if it's likely that my building has the allowed type of fittings, so that I could install either of the toilets I prefer, or if I should be considering a different type of toilet. I have found lots of reports on the web of people who have installed both Toto Drake and American Standard Champion in back to back installations and are indeed having the predicted problem. One of the reports actually shows pictures of the drainage pipes which seems to be the Y type, yet they are still having problems.

Does anyone have any useful insight?
 

Jadnashua

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Almost any of the low-flow toilets will flush fast enough for skipover without the proper fittings.

back_to_back_kohler.jpg
 
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Gary Swart

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Toto Drake instructions for back to back installations require a double sanitary tee-wye fitting.
 
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