I am in the process of adding a sink in our family room section of our
basement. The only close drain is a 3" waste / drain line which is fine
because I can get a 3" X 1-1/2" X 3" Tee to run the 1-1/2" drain line into.
My concern is since the 3" pipe is much more rigid than the smaller sizes,
how do I go about installing the tee section since there is minimal to no
upward movement of the 3" pvc pipe and I assume that I will need the 1-1/2"+
needed to get the 3" pipe over the lip and seated properly.
I saw was a 3" rubber sleeve with 2 metal band clamps that will do what I
want, but I am not sure they would be used for a permanent installation.
Do they make pvc sleeves that can be used like the copper sleeves for
in-place solders similar to the rubber sleeve mentioned above? If not can I
grind / sand out the separator in the middle of the connector so that it can
slide down and then be re-positioned similar to the 3" rubber sleeve?
Any help would be appreciated.
1) Glue a couple of stubs to the fitting to be inserted.
Cut out a section of the 3" stack 1/2" longer than the
new fitting w/stubs. Get (2) 3" No-Hub fittings. These have
a stainless band over the whole rubber. Slide them over the
stubs. Put the fitting in place and then slide the No-Hubs
back halfway onto the stack. Tighten.
2) Use a 3 X 1 1/2" WYE or long-turn TEE-WYE, not a san TEE.
3) The 1 1/2" drain must be vented downstream of the trap
to prevent siphoning since the stack already carries waste
from above. This may be the kink in the scheme.
Depending on local rules, you *might* be allowed to
use a mechanical vent (air-admittance valve).
Strongly suggest a talk with the inspector first.
Good idea on the stubs and two rubber sleeves. I was hoping that there will
be enough flex so that I would only need one rubber sleeve, but I will take
your suggestion just to be on the safe side. Since the bottom side is in
concrete, there will be no movement. Once I cut the pipe, I will be able to
better access the situation to see how much upward flex I have. I think
your suggestion will be the best way to handle it.
What is the difference between a WYE Tee and a San Tee? From the two
different styles I saw at the HD (though I don't remember the names), they
look to be the same on the 3" ends, just different ways of connecting the
1-1/2" sink drain. I assume that this is to prevent the waste from getting
into the drain line?
I have already gotten approval for an in-line vent from the county
inspection office. Worse case, I can tap into a vent line in another
portion of the house that is fairly easy to access, but I prefer the in-line
Thanks for your help,
A sanitary tee meets code in this instance, as long as the branch is
horizontal and the main line is vertical. If the main line was
horizontal, the fitting MUST be a wye or combination wye and 1/8th bend
(also called a tee-wye or wye-tee).
The tee will eliminate the need for a separate vent if the sink is
close enough to the main line. You may want a 2 inch branch instead of
1-1/2 inch, you can go further without a separate vent that way.
The branch MUST be sloped down in the direction of flow, usually 1/4"
drop per foot horizontal run.
How long is the horizontal branch going to be?
The Tee I have purchased to do this has a short 90 degree 1-1/2" branch off
of the 3" body. I did see one that has an elongated body and the 1-1/2"
branch is a longer curve starting from what looks like a Y branch from the
3" body. There was also a 3" section with that had a 1-1/2" branch that
look like a Y. I guess that is why the are called WYE branches?
The horizontal 1-1/2" branch will be less than 6' from the 3" vertical line.
I have the slope accounted for already, but thanks for the reminder. I
could as the county inspector if the 3" line will suffice for the vent given
that it is between 4-6' to the sink.
With 1-1/2 inch pipe I do not believe the sink can be 6 feet from the
stack without an additional vent. Please disreegard my previous post.
use the combination and a separate vent like Speedy Jim said. I will
check the code book Monday morning to see if there are any changes.
I went to Home Depot and they were having a fire prevention program
sponsored by the county fire department and building inspection department.
I was able to ask about the vents and he stated that Fairfax County will
approve a vacuum based in-line vent, not a mechanical (spring) based
version. Luckily, this is what I purchased so I am set for them. He also
clarified what type of rubber with steel sleeve connectors would be approved
when I splice the 3" drain / waste line.
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