why my toilet stop flushing

[Danielz]

I had an AAV installed, ugly but it worked for four years. I replaced the aav, but it did not work. When I took away the aav, old or new, it flushed. Does this mean there is a blockage on the way? The following is what I just drew.

I know it is ugly and not to code. I plan to redo it and get rid of this aav from the toilet. I installed an AAV under the vanity sink that is only two feet away from the toilet. But I am surprised to find out that this AAV does not help the toilet to flush. I do not know why.

I would appreciate it very much if you can point out the causes and suggest a solution.

 

[Jeff H Young]

maybe it was horribly plumbed and then you messed it up worse you could try re installing the AAV

 

[Sponsor]

 

[Danielz]

maybe it was horribly plumbed and then you messed it up worse you could try re installing the AAV

Thanks for your answer, but reinstalling it won't help because it is just a simple thing to remove it and put it back. I wonder how this can solve the problem.

 

[Reach4]

Very interesting.

Do you have a septic tank?

If you have a sewer, I expect that you have a belly in your drain piping. I could buy in to there being a blockage on the way.

 

[Jeff H Young]

Im going by what you said you removed it and it caused problems so put it back

 

[Danielz]

Very interesting.

Do you have a septic tank?

If you have a sewer, I expect that you have a belly in your drain piping. I could buy in to there being a blockage on the way.

No, I have the city sewage line. Are you saying that the sewage line is blocked somewhere? But why without the aav, and with a good opening, it flushes very well?

 

[Danielz]

Im going by what you said you removed it and it caused problems so put it back

if there is nothing there, it flushes very well, but when I put the aav back, new or old, it does not flush.

 

[Reach4]

I assume that you left the AAV port open when the toilet flushed well. That open pipe caused there not to be a backpressure. The air shoved ahead of the bunch of water from the toilet should get out of the way. There should be a dry path to a real thru-the-roof vent, or even if that was blocked, it should be able to move air ahead to the sewer.

What could stop that is a "belly" in the drain line that blocks the air flow to the effective vent. A partial clog could also stop the air once some water plugs the path. So I think belly, or partial clog. A camera could check the path to the sewer. Cheaper than a camera is to have a drain cleaning specialist clear out any partial clogs. That will not detect a belly, however.

 

[Danielz]

I assume that you left the AAV port open when the toilet flushed well. That open pipe caused there not to be a backpressure. The air shoved ahead of the bunch of water from the toilet should get out of the way. There should be a dry path to a real thru-the-roof vent, or even if that was blocked, it should be able to move air ahead to the sewer.

What could stop that is a "belly" in the drain line that blocks the air flow to the effective vent. A partial clog could also stop the air once some water plugs the path. So I think belly, or partial clog. A camera could check the path to the sewer. Cheaper than a camera is to have a drain cleaning specialist clear out any partial clogs. That will not detect a belly, however.

You are right in that there really exists a belly. When the amateur plumber installed the sewage line, there was a concrete wall between the toilet and the sewage pipe. He was lazy not hammering down the concrete, and as a result, there is a negative slope. I assume this is what you referred to as the belly. The negative slope is not significant, and in the past four years, the toilet was flushed very well with the AAV installed.

Are you saying that this belly or clog will prevent the toilet from flushing, even when I installed two AAVs. Why did not my second AAV work at all to help the toilet to flush?

I am going to cut open the toilet drain and install a 4 inch drain, do you think this thicker drain will help the water flush better? Or do you think I need to have that concrete wall hammered off from the bottom so that a good slope can be formed? The latter solution would need a lot of work.

 

[Danielz]

I was thinking if I put an AAV downstream, i.e., on the way where water goes, AAV should work, because there is not too much air pressure increasing when water is flushing in.

The reason the sink AAV did not help may be that it is located behind the toilet.

Am I right?

 

[Danielz]

In fact, I was thinking to install a 6-inch ABS pipe under the toilet. I wonder if this helps.

 

[Tuttles Revenge]

Or do you think I need to have that concrete wall hammered off from the bottom so that a good slope can be formed? The latter solution would need a lot of work.

The slope needs to be downwards the entire way. Gravity can not lift sewage up and over hills. No amount of increasing the pipe size will get over the belly. Do it the correct way once and be done with it.

 

[Reach4]

Are you saying that this belly or clog will prevent the toilet from flushing, even when I installed two AAVs. Why did not my second AAV work at all to help the toilet to flush?

An AAV keeps a significant vacuum from forming. A toilet is different. The toilet sends a gallon of water down the drain pipe, and air needs to get out of the way. So you need to avoid pressure ahead of that slug of water. An AAV will not relieve pressure; it only relieves a vacuum.

A house needs at least one vent thru the roof (VTR) , rather than having only AAVs. That lets the air get out of the way during toilet flushes. Also a sealed septic pit needs a VTR, because as waste water fills the sump, air must go elsewhere.

The toilet can get the air to avoid a vacuum forming behind the gallon from the bathroom air during the flush.

 

[Jeff H Young]

Id try to re [plumb the are to code or at least close

 

[Reach4]

If you have a belly, sometimes it is better to run the pipe out to the back yard, around the house, and connect to the line to the street.

In Alberta, your sewers are probably pretty deep. I don't know how much slope Canadian code requires on the sewer pipes.

 

[Danielz]

If you have a belly, sometimes it is better to run the pipe out to the back yard, around the house, and connect to the line to the street.

In Alberta, your sewers are probably pretty deep. I don't know how much slope Canadian code requires on the sewer pipes.

Thanks for your answers!

 

[Jeff H Young]

only one fix for a belly but might be a hack could help

 

[Danielz]

An AAV keeps a significant vacuum from forming. A toilet is different. The toilet sends a gallon of water down the drain pipe, and air needs to get out of the way. So you need to avoid pressure ahead of that slug of water. An AAV will not relieve pressure; it only relieves a vacuum.

A house needs at least one vent thru the roof (VTR) , rather than having only AAVs. That lets the air get out of the way during toilet flushes. Also a sealed septic pit needs a VTR, because as waste water fills the sump, air must go elsewhere.

The toilet can get the air to avoid a vacuum forming behind the gallon from the bathroom air during the flush.

Do you think AAV downstream the toilet will help relieve the pressure? probably not, as you said, the water is pushing forward and the air should have a place to go, if there is a belly in the way, the air will have nowhere to go. and thus the water cannot go either. I do have a vent to the roof in the house, however, this belly may prevent the air from getting access to it. Do you think a pressure-assisted toilet will help?

 

[Reach4]

An AAV cannot relieve pressure.

I am not a plumber. Regarding a pressure assist, I don't know. Maybe. A new toilet that uses less water usually flushes better than an old 5-gallon-per-flush toilet.

So the item that I think may help is to get a drain cleaning specialist to rod from the toilet flange to make sure the existing path with the belly is as good as practical. A little snake will not clean out your 3 or 4 inch pipe. Maybe see if you can get a combo deal of rodding with camera work.