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Back Outlet Blues

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darrink

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Hello all! First post, so here goes.
We remodeled a spare bedroom, adjoining our master bedroom, into a master bath. The house is built on a post tension slab, and coring through the footer was to risky due to not being able to positively identify the post tension cables, so the plumber recomended a back outlet toilet. I was reluctant, but decided to go with it to keep the bathroom layout we had decided on.

The toilet is on an outside wall, and the plumber installed a Kohler K-3578 back outlet toilet with a Sloan Flushmaster, and installed an AAV outside the house using a 3" sanitary tee with the 1.5" AAV directly on the outlet of the top run with a 3" X 1.5" bushing.

It never really flushed great, but the flushing became worse and worse regardless of solid or liquid waste. We replaced the AAV and it seemed to work better again, but not for long. It finally got to the point were it will not push the water out of the bowl, so I finally started some trouble shooting.

If I remove the AAV is flushes, but water comes out of the top run where the 1.5" AAV port is. My initial thought was the water was blocking the AAV just long enough to keep the toilet from flushing, and added an extension to the 1.5" pipe to raise the AAV to the 4" minimum suggested in the instructions. Again I was doubtful because I felt the water would still block the 1.5" AAV port regardless, but I tried it anyway, and it didn't work with the AAV installed, but did without it.

I then constructed a baffle to fit down inside the tee to divert the water downward when it entered the branch of the tee from the toilet, and not be able to block the 1.5" AAV port. That did not work, and still allowed water to come up out of the port. I removed the baffle and added a length of pipe to extend down into the tee so the water wouldnot be able to immediately block the hole. This was sccessful at keeping the water from coming back up through 1.5" AAV port, but it still did not allow the toilet to flush with the AAV installed. I am now convinced the added pressure from the pressure assist is closing the AAV not allowing it to work as it should.

Any positive input it appreciated.

Thanks Darrin
 

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Jeff Handy

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Seems likely the sewer drain is partially blocked.
Pull the aav and snake it out to the main line.
 

Geofd

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check with sloan or kohler, tell them you are using a mechanical vent ,there are some good articles on aav's
for negative pressure,and
positive air attenuators for positive pressure
 

breplum

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I agree with my esteemed fellow wiseguy, Jeff H: Snake it out first.
If you don't have a full 3" cleanout, then the tee needs to be drilled out with a Rambit or equal to create a full 3" permanent cleanout, with screw on or NoHub coupling + AAV higher up.
 

darrink

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Thanks for the quick responses. I had already planned to remove the bushing to be able to install the AAV higher on a 3" pipe. I will make it removable for future cleaning if needed. I will snake it tomorrow and see what I get. How should it be tied into the main line? Sanitary tee or 45. If I remember correctly, the line intersects 90 degrees to the main line.

I did call Kohler, and all they did was read me the questions from their troubleshooting guide on there website, almost word for word. I was not impressed. They said my problem was a venting issue. I have not reached out to Sloan, but I will.

Thanks!
 

breplum

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If your toilet is making the woosh, then there is nothing that Sloan can help with. The cartridge is readily replaceable, but the only way they fail is to not shut off completely.
You certainly don't need a three inch pipe riser.
A 3" stub of pipe, then a 3" no hub coupling connecting a 3 x 2 bushing, with a piece of 2" pipe. In the future, the cleanout is accessed by undoing the no hub coupling.
Or if you don't have 3" pipe. Buy a 3" spg x fip to glue in, and then a 3" mip adapter to receive the 3 x 2 bushing.
 

darrink

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The idea was to keep the riser as short as possible, so a short piece 3" pipe with an fpt adapter with a bushing is what I planned on.

Watching the water at the AAV port again, it looks like the water is coming out of the toilet so fast, it's hitting the back of the tee and coming up through the port before draining down.
I only have a small hand snake, so I'll see what I get today when I snake the line. It's a very short run to the main line, maybe 10 ft.

The Sloan is making a woosh sound, but I did notice some water in the bottom of the tank. Is that normal? Is the bowl compatible with and standard gravity tank?

Thanks!
 

Geofd

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Thanks for the quick responses. I had already planned to remove the bushing to be able to install the AAV higher on a 3" pipe. I will make it removable for future cleaning if needed. I will snake it tomorrow and see what I get. How should it be tied into the main line? Sanitary tee or 45. If I remember correctly, the line intersects 90 degrees to the main line.

I did call Kohler, and all they did was read me the questions from their troubleshooting guide on there website, almost word for word. I was not impressed. They said my problem was a venting issue. I have not reached out to Sloan, but I will.

Thanks!
Did you mention it was air assist flush
With Sloan mate internals??????
 

Jeff Handy

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A small snake might not operate properly in that big pipe.

You might need a thicker cable, otherwise it tends to just twist around onto itself when it hits a blockage.
 

darrink

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Did you mention it was air assist flush
With Sloan mate internals??????
It is a pressure assist with a Sloan Flusmaster.

A small snake might not operate properly in that big pipe.

You might need a thicker cable, otherwise it tends to just twist around onto itself when it hits a blockage.
I was able to snake the line and made it all the way to the septic tank with no issues, so I do not think there is any blockage.

......You certainly don't need a three inch pipe riser.
A 3" stub of pipe, then a 3" no hub coupling connecting a 3 x 2 bushing, with a piece of 2" pipe. In the future, the cleanout is accessed by undoing the no hub coupling.
Or if you don't have 3" pipe. Buy a 3" spg x fip to glue in, and then a 3" mip adapter to receive the 3 x 2 bushing.
I removed the 3" x 1.5" bushing and installed a short piece of 3" PVC, a no hub, and a 3" x 1.5" FPT bushing. The water still pushes up the pipe before it drains, but does flush, until I install the AAV. After I install the AAV I had the woosh, but the water doesn't leave the bowl.

Here is a link to video of what it does.


Any other suggestions are greatly appreciated.

Thanks!
 

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Jeff Handy

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With the AAV on, the flush water can not leave the bowl and enter the drain at full speed, because air is in the way.

A proper vent works in both directions, while an AAV only allows air to come in, not go out.

So you might need to change the vent to a taller column, with just an atmospheric vent, with a cap on it to keep debris and critters out.

Probably against code but should work.

Pros will advise.
 

Jeff Handy

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Your septic tank might need pumping.
Maybe the inlet or outlet are partially blocked, causing back pressure when air tries to get into there?
 

darrink

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Your septic tank might need pumping.
Maybe the inlet or outlet are partially blocked, causing back pressure when air tries to get into there?
Had the tanks pumped today, so I'll see if it makes a difference with the AAV installed.

Get a bigger AAV
I ordered a 3" but cancelled the order, thinking it would not help. If you seriously think it would help, I'll try it.

Does anyone know the requirements of a standard outside vent in Texas?

Thanks,
Darrin
 
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Geofd

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there is another article in another plumbing forum (terry love)talk about the same issue with the aav on it flushes terrible with the aav off it flushes fine but they also keep going back to it being clogged ,you could also contacy oatley i think they make aav 's see what they say
 

SHEPLMBR

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Had the tanks pumped today, so I'll see if it makes a difference with the AAV installed.


I ordered a 3" but cancelled the order, thinking it would not help. If you seriously think it would help, I'll try it.

Does anyone know the requirements of a standard outside vent in Texas?

Thanks,
Darrin
Can't hurt.
 
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