When to Use San-T or Tee-Wye

[hammerlane]

I'd like to install a laundry sink and washer in basement close to an existing 4" stack and have been looking for the proper way to do it or if I hire someone, to make sure they do it properly. I am kind of confused about San-Ts, San-Ts on their backs, Wyes, T-Wyes and the slew of fittings with their proper use.

In a previous post about tees and wyes in April 2011, Swade Plumbing said:

"Tee's on their back are no gouda.You have to have a "long sweep" pattern when going from vertical to horizontal. Wye's cannot be used to pick up fixture drains before the fixture vent. Example, a sink drain from the outlet of a trap needs to go to a Tee in the wall. This enables the vent to function properly and prevents trap siphonage."

When he said, "Wye's cannot be used to pick up fixture drains before the fixture vent" did he mean with the run of the wye in a vertical position and out of the branch of the wye a street 45 like in photo #1?

And correct me if I'm wrong but:
I also believe this arrangement of a Wye and a street 45 out of the branch of the Wye is called a "Combo and an 1/8".
And this "Combo and an 1/8" arrangement can also be found as one piece and is called a T-Wye?

Is the orientation of the T-Wye, in a horizontal position like in photo #2, where the branch of this horizontal T-Wye is for the stub out to the laundry sink OK?

Also look at photo #3 and see if that looks up to par.

Thanks

[dcman]

Re: When to Use San-T or Tee-Wye

Its either a tee or a wye...not t-wye...and just use a tee instead of a wye like in photo 1....

[hammerlane]

Re: When to Use San-T or Tee-Wye

What is the fitting in this photo called. Is this not a T-Wye? Thats what Ace Hardware calls it. Well whatever it's called when would you use it instead of a Wye?

Also is it OK to have fitting #1 oriented the way it is(kind of on its side in the horizontal position) in Photo #2 above?

Thanks

[ironranger]

Re: When to Use San-T or Tee-Wye

You will need to use a 4x2 san tee on your stack, not a combo etc.

[hammerlane]

Re: When to Use San-T or Tee-Wye

You will need to use a 4x2 san tee on your stack, not a combo etc.

OK I think I understand it is OK to use the san-tee on the stack because I'm going from horizontal to vertical. But is it ok to use the combo as I have it oriented in photo #2, where the branch of the combo would accept the stub for the sink?

Thanks

[dcman]

Re: When to Use San-T or Tee-Wye

Yes... but don't forget on the main stack to use a sanitary tee...

[Swade Plumbing]

Re: When to Use San-T or Tee-Wye

I'd like to install a laundry sink and washer in basement close to an existing 4" stack and have been looking for the proper way to do it or if I hire someone, to make sure they do it properly. I am kind of confused about San-Ts, San-Ts on their backs, Wyes, T-Wyes and the slew of fittings with their proper use.

In a previous post about tees and wyes in April 2011, Swade Plumbing said:

"Tee's on their back are no gouda.You have to have a "long sweep" pattern when going from vertical to horizontal. Wye's cannot be used to pick up fixture drains before the fixture vent. Example, a sink drain from the outlet of a trap needs to go to a Tee in the wall. This enables the vent to function properly and prevents trap siphonage."

When he said, "Wye's cannot be used to pick up fixture drains before the fixture vent" did he mean with the run of the wye in a vertical position and out of the branch of the wye a street 45 like in photo #1?

And correct me if I'm wrong but:
I also believe this arrangement of a Wye and a street 45 out of the branch of the Wye is called a "Combo and an 1/8".
And this "Combo and an 1/8" arrangement can also be found as one piece and is called a T-Wye?

Is the orientation of the T-Wye, in a horizontal position like in photo #2, where the branch of this horizontal T-Wye is for the stub out to the laundry sink OK?

Also look at photo #3 and see if that looks up to par.

Thanks

The fitting in your posted picture is what plumbers commonly refer to as a Combination Wye-1/8 bend or "comby" in the vernacular. Your diagram looks ok except that I would use a sanitary tee instead of the combination wye-1/8 bend for the vent.

[Swade Plumbing]

Re: When to Use San-T or Tee-Wye

You will need to use a 4x2 san tee on your stack, not a combo etc.

Ranger, as long as he pulled the vent off of the fixture branch like he shows in picture 3 (except with a sanitary tee for the vent) wouldn't it be ok to use the comby on the stack? The stack isn't serving as a vent, in fact I think that the stack is a sanitary stack for a bathroom on the upper floor (if I had to guess).

[hammerlane]

Re: When to Use San-T or Tee-Wye

The fitting in your posted picture is what plumbers commonly refer to as a Combination Wye-1/8 bend or "comby" in the vernacular. Your diagram looks ok except that I would use a sanitary tee instead of the combination wye-1/8 bend for the vent.

Swade---which of my photos are you referring to when you say, "I would use a sanitary tee instead of the combination wye-1/8 bend for the vent". In photo #3 I Have a San-T off of the Combo.

Also the 4" stack in the photo is servicing only 2 floor drains in my garage. You can see about 7 feet up on the stack where the 4" San-T ties in to pick up the floor drains. On top of this 4" San-T is a bushing for the 2". The 2" serves as a vent. This is the vent I was planning on tieing into for the laundry sink / washer standpipe set-up.

[Swade Plumbing]

Re: When to Use San-T or Tee-Wye

Swade---which of my photos are you referring to when you say, "I would use a sanitary tee instead of the combination wye-1/8 bend for the vent". In photo #3 I Have a San-T off of the Combo.

Also the 4" stack in the photo is servicing only 2 floor drains in my garage. You can see about 7 feet up on the stack where the 4" San-T ties in to pick up the floor drains. On top of this 4" San-T is a bushing for the 2". The 2" serves as a vent. This is the vent I was planning on tieing into for the laundry sink / washer standpipe set-up.

I just looked at your picture again. If you are planning to install a washer standpipe and a utility sink then you would need a separate vent for each fixture. You would use a san tee in the horizontal position just downstream of the trap for the standpipe. As long as you tie the vents for the new fixtures into an existing vent stack and not into a drain you will be fine. I don't really have a way to make a diagram and post it, sorry if it's confusing.

[hammerlane]

Re: When to Use San-T or Tee-Wye

I just looked at your picture again. If you are planning to install a washer standpipe and a utility sink then you would need a separate vent for each fixture. You would use a san tee in the horizontal position just downstream of the trap for the standpipe. As long as you tie the vents for the new fixtures into an existing vent stack and not into a drain you will be fine. I don't really have a way to make a diagram and post it, sorry if it's confusing.

Swade....do you mean like fitting #5 in this new photo?

Also I spoke with our local inspector. When I told him laundry sink and washer standpipe, he said any horizontal run to the stack after the washer standpipe has to be 3" or larger. Says the standpipe ca be 2" but the horizontal run to the stack has to be 3" or larger??

I am going to start a new post on this topic to see if anyone else has been told this.

The 4" stack in the photo is servicing only 2 floor drains in my garage. You can see about 7 feet up on the stack where the 4" San-T ties in to pick up the floor drains. On top of this 4" San-T is a bushing for the 2". The 2" serves as a vent. This is the vent I was planning on tieing into for the laundry sink / washer standpipe set-up. No other fixtures in the house drain into this stack above where you see the San-T picking up the garage floor drains. Its all venting above that. So would it be OK to tie in as I propose for venting?

Thanks

[Flux]

Re: When to Use San-T or Tee-Wye

Your inspector wants a 3" branch?

My question to the inspector would be, "how would a single fixture wash the walls of the 3" pipe?"

Also, you're within distance of not needing a back vent, but your diagram is wrong regarding where the back vent should tie in. Back vents are suppose to tie in 6" or above the highest fixture's flood rim on that line. So if you're in a 2 story house, that vent is suppose to follow the stud pocket all the way to the second floor and be 6" higher than the sink's flood rim on that line. There is noting wrong with giving every fixture in your house it's own vent, but I'm going to assume your code allows back-venting..as it should.

[ironranger]

Re: When to Use San-T or Tee-Wye

Just curious why you called the inspector, this is your house right?

[hammerlane]

Re: When to Use San-T or Tee-Wye

Your inspector wants a 3" branch?

My question to the inspector would be, "how would a single fixture wash the walls of the 3" pipe?"

Also, you're within distance of not needing a back vent, but your diagram is wrong regarding where the back vent should tie in. Back vents are suppose to tie in 6" or above the highest fixture's flood rim on that line. So if you're in a 2 story house, that vent is suppose to follow the stud pocket all the way to the second floor and be 6" higher than the sink's flood rim on that line. There is noting wrong with giving every fixture in your house it's own vent, but I'm going to assume your code allows back-venting..as it should.

The 4" stack in the photo is servicing only 2 floor drains in my garage. You can see about 7 feet up on the stack where the 4" San-T ties in to pick up the floor drains. On top of this 4" San-T is a bushing for the 2". The 2" serves as a vent. This is the vent I was planning on tieing into for the laundry sink / washer standpipe set-up. No other fixtures in the house drain into this stack above where you see the San-T picking up the garage floor drains. Its all venting above that. So would it be OK to tie in as I propose for venting?

[Flux]

Re: When to Use San-T or Tee-Wye

I don't know what Plumbing code your state follows, but the I.P.C. allows 6 feet before you have to back vent the fixture. I'm going to assume whatever code your state follows...6 feet would be plenty as well.

You don't need that backvent...don't waste your time with it either, unless the inspector specifically asks for it. The way you have it drawn up in your photo just doesn't make logical sense to do it, because you're that close to the stack anyways.

Why not just dump the washing machine into the laundry sink, instead of installing a separate laundry box? Because if you do it the way your photo shows, you will have 2 fixtures behind a vent, and "it will" have to be back vented.