Back to back new toilets 2019

[TinaS]

Still an issue in 2019! If we would of known we would of tried to keep repairing old model. Nothing plumber has done has solved our issue.

Plumber has tried vent, etc. and we still has a "geyser" in downstairs toilet when upstairs one is flashed and the water drains out. Uploaded pictures, the new vents, pipes are on right and can see what is new after jackhammering floor.

We cant afford to keep "fishing" for a solution. People should be told this can happen with any new toilet purchase if they have a back to back.

Solution that will work would be appreciated!

 

[Reach4]

Confirm that https://terrylove.com/forums/index.php?attachments/20191030_133528-jpg.56786/ is the upstairs toilet, or if the downstairs toilet, identify what the two big vertical pipes from above are.

Back-to-back toilets are on the same floor, and usually separated by just a wall.

 

[Sponsor]

 

[Tuttles Revenge]

I would suspect that if you have water geysering out of the downstairs toilet when the upstairs toilet is flushed that you have something clogging the main drain downstream of where the two toilet drains connect together. Water takes the easiest path (except when your roof is leaking) and to force water to go backwards up a drain and push the water in the toilet trap is a lot of effort.

Changing the toilet itself is not ever going to solve the root cause of your problem.

What has changed since the house was originally built or before the issue started?

 

[TinaS]

Confirm that https://terrylove.com/forums/index.php?attachments/20191030_133528-jpg.56786/ is the upstairs toilet, or if the downstairs toilet, identify what the two big vertical pipes from above are.

Back-to-back toilets are on the same floor, and usually separated by just a wall.

the upstairs toilet pipe is on the right in the picture . The downstairs toilet is directly underneath the upstairs one on the lower level. The t "joint" that was built in 1976 is under the foundation wall and we were told that trying to change that to a wye where the original house builder installed it is a huge risk and they will not try that solution after seeing how/where it is.

 

[TinaS]

I would suspect that if you have water geysering out of the downstairs toilet when the upstairs toilet is flushed that you have something clogging the main drain downstream of where the two toilet drains connect together. Water takes the easiest path (except when your roof is leaking) and to force water to go backwards up a drain and push the water in the toilet trap is a lot of effort.

Changing the toilet itself is not ever going to solve the root cause of your problem.

What has changed since the house was originally built or before the issue started?

It started when our old ceramic toilet was changed upstairs to a 1.6 flush

 

[TinaS]

I would suspect that if you have water geysering out of the downstairs toilet when the upstairs toilet is flushed that you have something clogging the main drain downstream of where the two toilet drains connect together. Water takes the easiest path (except when your roof is leaking) and to force water to go backwards up a drain and push the water in the toilet trap is a lot of effort.

Changing the toilet itself is not ever going to solve the root cause of your problem.

What has changed since the house was originally built or before the issue started?

Today we had our septic cleaned out again and when they looked it wasn't full. After emptying they had us flush the toilet and saw the water freely flowing into the tank. However the "geyser " still occurs in downstairs along with the water being pulled out of the bowl when the upstairs toilet is flushed.

 

[Tuttles Revenge]

Today we had our septic cleaned out again and when they looked it wasn't full. After emptying they had us flush the toilet and saw the water freely flowing into the tank. However the "geyser " still occurs in downstairs along with the water being pulled out of the bowl when the upstairs toilet is flushed.

I would send a camera down the drain. The toilet fixtures themselves can't cause this, but something perhaps did happen when the toilets were changed. Maybe someone dropped a tool or a something down the drain? When I see the above scenario play out on jobsites it screams blockage in the main line. Flushing a toilet shouldn't create enough positive pressure to move another fixtures water level much more than fractionally. Positive pressure implies that the main drain and associated vents are blocked from allowing air to flow freely.

Even if they saw water freely flowing.. you can push water with water.. if your pipe has a belly or a bow in it.

 

[TinaS]

Confirm that https://terrylove.com/forums/index.php?attachments/20191030_133528-jpg.56786/ is the upstairs toilet, or if the downstairs toilet, identify what the two big vertical pipes from above are.

Back-to-back toilets are on the same floor, and usually separated by just a wall.

that picture is the new vent they put in for downstairs toilet

 

[Jadnashua]

What I think you need is a Wye for the lower toilet versus a T. It probably won't resolve itself unless you do, or, you can reroute the upstairs toilet to join the drain below that toilet. All newer toilets tend to flush faster versus the older, often much larger capacity ones. I think it is that velocity that is causing your issue unless there's a restriction in the line below the lower toilet, forcing the water into that toilet versus continuing down the drain. NOte, gravity is the same, but the volume/time is greater with the newer toilets so it pushes a bigger air plug ahead of it.