As a result of a remodeling job, the workers capped off a sewer pipe
that was once properly vented out the roof. They must not have
realized that I had a basement bar sink that is a part of same set of
drain pipes.

My symptom was that the bar sink would no longer drain properly. This
made sense to me: there needs to be a vent so that air can be drawn in
to help the system drain.

The OTHER symptom was sewage getting sucked through the bar sink P-
trap and belching up a foul sludge into the sink (I've remodeled my
bathrooms before and have had my head nearly in the toilet sewer hole
and yet I've NEVER smelled a smell like this). This was strange, this
part of the sewer circuit is not active and should not have material
in it.

Does the vent also serve other purposes other that proper drainage?
Without it, does it create some sort of, I don't know, vacuum that
pulls sewage towards pipes that would otherwise be clear?

Connecting this pipe back up with the vent in the roof would be a
considerable effort. So I put an indoor vent cap on the end of the
pipe. It supposedly lets air in but won't allow are to come out. I
don't get sludge backups anymore but I do get sewer smell. I take it
that these indoor vent caps don't work very well.

djh wrote:

As a result of a remodeling job, the workers capped off a sewer pipe
that was once properly vented out the roof. They must not have
realized that I had a basement bar sink that is a part of same set of
drain pipes.

My symptom was that the bar sink would no longer drain properly. This
made sense to me: there needs to be a vent so that air can be drawn in
to help the system drain.

The OTHER symptom was sewage getting sucked through the bar sink P-
trap and belching up a foul sludge into the sink (I've remodeled my
bathrooms before and have had my head nearly in the toilet sewer hole
and yet I've NEVER smelled a smell like this). This was strange, this
part of the sewer circuit is not active and should not have material
in it.

Does the vent also serve other purposes other that proper drainage?
Without it, does it create some sort of, I don't know, vacuum that
pulls sewage towards pipes that would otherwise be clear?

Connecting this pipe back up with the vent in the roof would be a
considerable effort. So I put an indoor vent cap on the end of the
pipe. It supposedly lets air in but won't allow are to come out. I
don't get sludge backups anymore but I do get sewer smell. I take it
that these indoor vent caps don't work very well.


The "vent cap" is a mechanical vent that should not allow
sewer gas to escape. But it may not be an adequate solution
to the overall venting problem.

Not nearly enough info. You would have to post a diagram
of the complete venting/drainage layout.

In the end, a proper roof vent may need to be installed.

Jim

Depending on the plumbing layout, there must be some water/sludge that
settles in the pipe leading to the bar sink, when upstairs facilities
particularly a toilet is flushed, enough pressure must be forcing this
sludge up and into the sink. The exterior vent that was connected to the
sink must have relieved the air pressure in the drain line and did it's job,
however, it sounds like the bar sink line is not draining well, and may be
allowing sewage to back up into its line causing the foul burps. The pipe
may need to be properly sloped towards your main drain line as the sludge
burps may end up clogging any new vent line and/or may continue to discharge
into the sink. Either that or your main sewer line is partially blocked
preventing the sewage from exiting in a steady flow, instead it may be
causing a backup into your sink. You may want to get a plumber out to check
for any blockage between your stack and the street sewer.

"Speedy Jim" wrote in message
. net...
djh wrote:

As a result of a remodeling job, the workers capped off a sewer pipe
that was once properly vented out the roof. They must not have
realized that I had a basement bar sink that is a part of same set of
drain pipes.

My symptom was that the bar sink would no longer drain properly. This
made sense to me: there needs to be a vent so that air can be drawn in
to help the system drain.

The OTHER symptom was sewage getting sucked through the bar sink P-
trap and belching up a foul sludge into the sink (I've remodeled my
bathrooms before and have had my head nearly in the toilet sewer hole
and yet I've NEVER smelled a smell like this). This was strange, this
part of the sewer circuit is not active and should not have material
in it.

Does the vent also serve other purposes other that proper drainage?
Without it, does it create some sort of, I don't know, vacuum that
pulls sewage towards pipes that would otherwise be clear?

Connecting this pipe back up with the vent in the roof would be a
considerable effort. So I put an indoor vent cap on the end of the
pipe. It supposedly lets air in but won't allow are to come out. I
don't get sludge backups anymore but I do get sewer smell. I take it
that these indoor vent caps don't work very well.


The "vent cap" is a mechanical vent that should not allow
sewer gas to escape. But it may not be an adequate solution
to the overall venting problem.

Not nearly enough info. You would have to post a diagram
of the complete venting/drainage layout.

In the end, a proper roof vent may need to be installed.

Jim

Thanks for your responses! I threw together a crude diagram and posted
it below.

http://picasaweb.google.com/danjhigg...91318589685202

The theory that waste is working into the bar sink line and pressure
is pushing it through the P-trap is interesting. I'm
guessing that the waste is from the kitchen and that bathroom waste
isn't going to work its way all the way back to the
other side of the house.

I'm holding off bringing in a plumber until I better understand the
problem. The last plumber I had (for a different problem) wasn't very
thoughtful about root causes.

-dan

djh wrote:

Thanks for your responses! I threw together a crude diagram and posted
it below.

http://picasaweb.google.com/danjhigg...91318589685202

The theory that waste is working into the bar sink line and pressure
is pushing it through the P-trap is interesting. I'm
guessing that the waste is from the kitchen and that bathroom waste
isn't going to work its way all the way back to the
other side of the house.

I'm holding off bringing in a plumber until I better understand the
problem. The last plumber I had (for a different problem) wasn't very
thoughtful about root causes.

-dan


Excellent diagram.

Your mechanical vent should properly protect the bar sink trap.

Any fluids backing up in the bar sink can only be due
to some restriction in the main drain/sewer. As you said,
more likely the kitchen.

The mech vent can't prevent backup like this as it will
close as soon as it feels any pressure in the line.
The original roof vent would relieve the pressure but it
isn't there to prevent backups either.

At this point, I would focus on clearing any obstruction (snake)
or at least replicating the backup under controlled condition
to pinpoint why it is happening. For example, flush large
quantities of water down the kitchen sink rapidly. Do same for
bath toilet and, especially, for the laundry.

Jim

Excellent. Thanks for your comments Jim!
-dan

In article . com,
says...

Connecting this pipe back up with the vent in the roof would be a
considerable effort. So I put an indoor vent cap on the end of the
pipe. It supposedly lets air in but won't allow are to come out. I
don't get sludge backups anymore but I do get sewer smell.

Is the smell constant, or does it come and go with other drain use?

If it's constant, have you taken apart the sink trap and cleaned the
rest of the drain very thoroughly? Is it possible you're smelling
something that got left behind by one of the sludge burps?

--
is Joshua Putnam
http://www.phred.org/~josh/
Updated Infrared Photography Gallery:
http://www.phred.org/~josh/photo/ir.html

I appreciate the comments. This has been helpful.

From this thread, I've learned:

The plumbing connects (under the concrete) in such a way that kitchen
waste can easily back up into the pipes leading to the bar sink.
Subsequent pressure from the active kitchen pipes apply pressure on
the wayward waste and eventually push it towards the sink.

Reconnecting the vent from the bar sink may help but it may not. The
bar sink is close enough to the kitchen line to benefit from its
vent.

I'm thinking about re-running the bar sink to the vertical kitchen
line so that its properly sloped plus use a sloping connecting piece.
This way no waste can back into it.
-dan

djh wrote:
I appreciate the comments. This has been helpful.

From this thread, I've learned:

The plumbing connects (under the concrete) in such a way that kitchen
waste can easily back up into the pipes leading to the bar sink.
Subsequent pressure from the active kitchen pipes apply pressure on
the wayward waste and eventually push it towards the sink.

Reconnecting the vent from the bar sink may help but it may not. The
bar sink is close enough to the kitchen line to benefit from its
vent.

I'm thinking about re-running the bar sink to the vertical kitchen
line so that its properly sloped plus use a sloping connecting piece.
This way no waste can back into it.
-dan



Oh, if you can make that connection it may solve it.
Use a WYE or a long-turn TEE-WYE for the connection.
The mechanical vent you already have will admit air
as the kitchen sink drains, preventing siphonage of the
bar sink trap. You may hear the mech vent "chatter"
as the kitchen drains.

Jim