Battling Totos

Hello all. New to this forum and I'm hoping someone can help me.

Three or so years ago I read here about the Toto toilets, purchased and installed my first Drake and have loved it ever since. Recently, the tank cracked on our other toilet, so I did not hesitate and replaced it with a Drake, too.

The two toilets are "back-to-back" and share the same standpipe. The problem is, when either of the toilets is flushed, it pulls water down from the other also. I think the first Toto had this affect on the other older toilet, but it had substantially more water in the bowl so it was not as noticeable. Now, after two or three flushes from one, the other has a practically empty bowl.

Is this a problem with the vent stack not being large enough or something? Is there something easy I can do or add to alleviate this phenomena?

Any advice or help would be greatly appreciated.

RG

Did you read the instructions that came with the Drake on back to back installation? There is a right way to do it, but I don't remember exactly what the details are.

The plumber who installed the piping did not use the proper fitting for back to back toilets and it wasn't a big deal on the older, slower flushing water hogs. The newer toilets use a siphon jet to get the water moving much faster than the older ones, and you may need to replace it. If you look at the end of the spec sheet, Toto warns of exactly this problem. http://totousa.com/Portals/0/ProductDownloads/SS-00355,%20CST743S,%20V.02.pdf

Ok, I am really embarrassed; no, I did not think to check the instructions for that. I will try to find them tomorrow and see what I should have done!
Thanks,
RG

Yes, that is exactly it. We have a Tee and not a Wye. What's worse, it actually has another leg which drains the back-to-back showers. This oughta be a fun one!

Thanks!
RG