Self draining toilet?

[Vernonv]

Hi all,
We have this strange thing happen with our toilet, where the s-bend in the pan will sometimes empty and allow a rather nasty smell through.

It happens quite often (every few weeks) to the en-suite toilet and on rare occasions to the main toilet.

My wife reckons it coincides with windy days, but I'm not so sure.

We are on a septic system.

Any ideas on what might be causing this and how it could be fixed???

[Matt88s]

I'm not sure what the problem is, but more than likely that "bad" smell is sewer gas which has some nasty health effects, and is also highly flammable. So you'll want to get on the problem pronto.

http://en.wikipedia.org/wiki/Sewer_gas

[OBBob]

I would check the vents first. A block vent can do very stange things, also wind 'may' effect the venting? If it's clear, maybe check there is a good cover that will defuse the wind at thge top of the vent ... if that l;ooks like it could be doing it (although I haven't heard of wind as a reason before)?

[Iain]

We had that problem once and the plumber explained that it was a build up of gas that exits through the dunny then after the eruption sucks the contents of the 'S' bend back in, a blocked vent is a likely source of the problem.

[ozwinner]

There must be a vent upstream of the dunny or at the dunny itself.

Al :)

[Vernonv]

There is one vent that I am aware of and I think the toilet in question is between it and the septic tank.

I have included a photo of where the vent line comes up. How do I go about checking that the vent line is clear?

[masoth]

I'm sure I will not overcome your problem with this post, however, the first thing I'd do is remove the ivy type growth from the area near the drainage.

soth

[rodm]

At the top of that pipe there will be a cap with slots. Sometimes paint covers these slots and will cause problems.

[I_wanna_Shed]

Hi all,
We have this strange thing happen with our toilet, where the s-bend in the pan will sometimes empty and allow a rather nasty smell through.

It happens quite often (every few weeks) to the en-suite toilet and on rare occasions to the main toilet.

My wife reckons it coincides with windy days, but I'm not so sure.

We are on a septic system.

Any ideas on what might be causing this and how it could be fixed???


We had this problem along with our neighbour. We both noticed it occured on windy days. I wrapped 2 layers of flyscreen around the vent on the top of the vent pipe, which solved the issue (the flyscreen must have 'diffused' the wind enough). I guess the wind blowing across the top of the pipe creates some sort of vacuum, lowering the water level in the bowel and hence letting gases escape.

[Bodgy]

We get the same on windy days, although the level only drops about 20mm, never enough to break the water seal.

My guess would be the wind passing over the vent causes a partial vacuum in the sewer line, same as the Venturi principle.

If this is correct (and I'm far from certain) then disturbing the airflow across the top of the vent would stop it. Dirty air would not create the same partial vaccuum.

[ozwinner]

How do I go about checking that the vent line is clear?

There are smoke generators that are available to see if the vent is working, maybe hire one from Kennards if they have one. :?

You stick the smoke generator in the pipe down stream of the vent and smoke away..:p

I cant see it being vacuum from wind as once the water seal is broken then no more water should be sucked down as the vacuum seal is broken and the water should stay at the "just" broken seal stage.

A faulty or inadequate vent will suck your dunny dry, water flow from other sources will create greater vacuum than the wind and suck the dunny dry in one big gulp.


But hey, Im a bricklayer, what would I know? :U

Al :)

[Vernonv]

Thanks everyone for their input, it's much appreciated.

First, I think I'll try eliminating the wind issue by restricting it's effects on the vent pipe.

If that fails I check for blockages - I'll have to see if I can get one of those smoke machines.

Thanks again everyone.

[ozwinner]

Failing the smoke machine, get some old cotton rags and light them so that they smoulder, same thing as a smoke machine and cheaper, just make sure you take them off before you light them. :p

Al :)

[Vernonv]

Failing the smoke machine, get some old cotton rags and light them so that they smoulder, same thing as a smoke machine and cheaper, just make sure you take them off before you light them. :p

Al :)


Now you got me looking around for the hidden camera ... honestly i don't wear them out:D !!!!!