Drainage help

[dan_2007]

Hi,

When our tub is drained most of the time it will make a bubbling noise in the sink drain. The plumbing in the bathroom is as follows:

The end of the line is at the sink which then runs 7' to a T.

From the T the pipe continues to a vent line that hooks into the main Stake and the 90 degree part of T continues for about 2' and the tub hooks in.

From there it continues for about 2' and then drains into the main stake.

At the present time there is about 2" of pitch on the 7' stretch to the sink.

I was wonder what the easiest option is to fix this problem, should I add alot more pitch to the line?

 

[hj]

piping

You start at the lavatory, but do not tell us anything about the lavatory drain piping. If what you describe is all there is to it, then the sink is not vented and that is the cause of your problem.

 

[Sponsor]

 

[dan_2007]

Hi,

Yes there is not a vent at the sink just at the T. We have recently installed a tub & sink with a pop-up drain and I think it has intensified the sound because I have never noticed it before.

Now to vent this, can I run a pipe that hooks into the existing vent at the T and run it parallel to the 7' stretch to the sink and hook it up before the trap or does it need to hook in at the sink and go through the roof?

Is 2" of pitch on the 7' stretch enough or should it be angled more?

Thanks for the reply,
Dan

 

[dan_2007]

I also forgot to add that all piping is 1.5" abs pipe(black plastic), vent included and it drains into a 4" cast iron stake.

 

[Markts30]

2" in 7' is good for slope...
Search the forum for discussions on studor vents..
There have been numerous threads where this possible solution to your problem has been discussed...
In a nutshell, an AAV at the lav (out the top of a santee) should be adequate for venting it...
Check the code in your area to see if they are legal...
Others may have better ideas...