Single to Double Vanity Plumbing

[Nav360]

Hello,

I'm currently working on a bathroom remodel, and finally have to do the plumbing for the double sink vanity that will be installed. I'm trying to figure out the best approach without cutting any corners that will cause issues in the future. I was going to use the examples I've seen on the forum, but none of those examples have a HVAC condensation line tied into the original drain. My plan was to use the exact example below, and create something like this, but the problem I'm running into is I can't split off the drain because the HVAC line from the attic is on the right of it. There is not enough room between the stud to run a 2" PVC across that condensation line. The second sink will be going to the right of the current plumbing if that helps get a better image of the end result. Looking for any advice/tips to make this happen. I'm located in Texas if that makes any big differences with plumbing codes

 

[wwhitney]

the problem I'm running into is I can't split off the drain because the HVAC line from the attic is on the right of it. There is not enough room between the stud to run a 2" PVC across that condensation line.

Say your DWV layout will work by using a double fixture fitting at the appropriate height, with the vent straight up and the common drain straight down. Then the HVAC condensate drain should go to a sink tailpiece with a branch inlet, while maintaining slope to drain. That means it would stub out of the wall well above the height of the trap arm. So I don't see how the condensate drain will interfere with your DWV within the wall.

Cheers, Wayne

 

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[Nav360]

Say your DWV layout will work by using a double fixture fitting at the appropriate height, with the vent straight up and the common drain straight down. Then the HVAC condensate drain should go to a sink tailpiece with a branch inlet, while maintaining slope to drain. That means it would stub out of the wall well above the height of the trap arm. So I don't see how the condensate drain will interfere with your DWV within the wall.

Cheers, Wayne

That's makes sense I was just worried if the double fixture had to be a certain height per code. If install the fixture tee right below the condensation line how would I increase or what fitting would I need to increase the height of the trap arms on both sinks? My second question is when installing the condensation into the tailpiece does it just need to be high than the p-trap to drain correctly?

I created (tried) to make a diagram of the end result.

White - Vent Pipe 1-1/2"
Green - Drain Pipe 2"
Red- DWV Double Fixture Fitting 2"x1-1/2"x1-1/2"x1-1/2" ( I can't seem to be able to locate this anywhere local. Open to suggestions on how to source it.)
Blue - 1-1/2" Trap Arm's
Yellow - This is lowest point I can install the fixture fitting in order to avoid interference with the condensation line.

 

[John Gayewski]

Just to say it differently. You don't tie the condensate into the drain inside of the wall. They both have to come out of the wall before the can tie together.

The condensate goes into your new sink drain below the bowl in the cabinet.

 

[Nav360]

Just to say it differently. You don't tie the condensate into the drain inside of the wall. They both have to come out of the wall before the can tie together.

The condensate goes into your new sink drain below the bowl in the cabinet.

Yep I understand that, but now I'm curious if it's ok use some type of hose to go into the branch tailpiece rather than PVC all the way? Something like the picture below. Assuming it would need to be a 1-1/2" branch piece with a 3/4" drain connection, which I can't seem to find unless I'm searching for the wrong thing.

Really appreciate all help

 

[John Gayewski]

Yep I understand that, but now I'm curious if it's ok use some type of hose to go into the branch tailpiece rather than PVC all the way? Something like the picture below. Assuming it would need to be a 1-1/2" branch piece with a 3/4" drain connection, which I can't seem to find unless I'm searching for the wrong thing.

Really appreciate all help

Yeah that would be fine, but your gonna want pipe protruding from the wall. You don't want to have a hose connection in the wall. Once your out of the wall anything you can find will work. It'll just need to be serviceable.

 

[Reach4]

One comment: if your flex pipe is black, it will not get scuzzy looking over time.

 

[Nav360]

One comment: if your flex pipe is black, it will not get scuzzy looking over time.

Noted!

Thanks for the tip

 

[Nav360]

What would be correct type of 90 degree fitting to come off the trap arm for the stub out? Marked in red below

 

[John Gayewski]

Technically a long sweep. But since your right at the surface of the wall everyone uses quarter bends.

 

[Nav360]

Pulled the boards off the front, and it looks like they used a long sweep 90 off the current tee that's in place. For some reason I thought there was a minimum trap arm length required in Texas.

 

[GReynolds929]

Pulled the boards off the front, and it looks like they used a long sweep 90 off the current tee that's in place. For some reason I thought there was a minimum trap arm length required in Texas.



View attachment 94725

There is, and that trap arm is more than long enough.

 

[wwhitney]

For some reason I thought there was a minimum trap arm length required in Texas.

Minimum trap arm length is 2 pipe diameters. Almost impossible to violate on a sink.

Cheers, Wayne

 

[John Gayewski]

Are you sure that's a long sweep? It doesn't o on like one to me. But I'm pretty far from Texas.

 

[Nav360]

Are you sure that's a long sweep? It doesn't o on like one to me. But I'm pretty far from Texas.

You are correct it's not a long sweep as I thought it was. It says D300-015 which shows up as "1½ DWV 1/4 Bend". I know you said a quarter bend would work since It's right at the surface, but either I can't find it or I'm confused with the all the different types of 90's sold. I bought the fitting below, but not sure if it's the correct one.

https://www.lowes.com/pd/Charlotte-Pipe-1-1-2-in-x-1-1-2-in-dia-90-Degree-PVC-Schedule-40-Hub-Elbow-Fitting/3132773

 

[Jeff H Young]

My code requires a long sweep its commonly ignored . Your trap arm lenght is fine.
Id be thinking about where to cut that later to make your new sink connection your fittings are close together Maybe cut the pipe flush on the 90 and remove pipe from hub with a ram bit

 

[John Gayewski]

You are correct it's not a long sweep as I thought it was. It says D300-015 which shows up as "1½ DWV 1/4 Bend". I know you said a quarter bend would work since It's right at the surface, but either I can't find it or I'm confused with the all the different types of 90's sold. I bought the fitting below, but not sure if it's the correct one.

https://www.lowes.com/pd/Charlotte-Pipe-1-1-2-in-x-1-1-2-in-dia-90-Degree-PVC-Schedule-40-Hub-Elbow-Fitting/3132773

Yes thats a quarter bend.

 

[Nav360]

Yes thats a quarter bend.

Thanks!

 

[Nav360]

Any tip's/tricks to getting a proper 1/4" slope on the trap arms when going through the studs? I'm going to be adding additional framing in, but wanted to know ahead of time of anything I should do differently.

 

[John Gayewski]

16" centers is about 5/16" per stud.

I would say normally, when routing through studs, the 1/4" per ft is not follwed as close. Also when going through more than about 3 you'll have to detach the stud and move it to get the pipe in there. You shouldn't hopefully be going through that many.