Elevation difference for successful PVC mating?

[Alex S]

Hi there,

I have a new toilet install happening where the 3" closet elbow under the toilet is 14ft away from the 4" main drain that I will be WYE fitting into at a 45. (4x4x3 here).

If the closet elbow sits just under neath the toilet flange (+ room for connection) The elevation difference is 17.5" from the main drain to the elbow under the toilet.

Fall isn't an issue per say, 1/4" per foot means I need 3.5" of fall. No issue on not enough fall, but rather the opposite

My question is how would this typically be done? Would you drop the closet elbow under the toilet a bit to allow the connection to make up?

I am fearful that I will approach the WYE at too aggressive of an angle to make up the connection.

I'm sure there is a "maximum approach angle" or something to that effect that dictates you must come in at a fitting without too much slope or the connection would never be possible.

See the image for what I am asking, but I think my question is pretty straight forward:

How do you deal with making up the connection when allowing fall? Is there a measurement you make to ensure the connection will mate up? Or is this eyeballing and experience?

Thanks guys so far you have been hugely helpful.

 

[Master Plumber Mark]

I would not worry about it so much... just throw a few street 45s in the line at the connection
and forget about it... There is probably no such thing as too much fall ..... the turds will not
know the difference or really complain very much about it.....

Too little fall or no fall is a much worse problem to have

 

[Sponsor]

 

[Jadnashua]

The wye can handle the velocity without issues.

 

[hj]

I doubt that any inspector is going to allow a 14' run without a vent, especially into a "Y"

 

[Master Plumber Mark]

I doubt that any inspector is going to allow a 14' run without a vent, especially into a "Y"

Actually in our state its ok the last I looked....

 

[Alex S]

Haha sorry, I omitted the vent as it was not applicable. Yes there is a 2" vent 3 ft from the closet elbow that goes up the wall. Sorry that was not clear.
It wasnt a velocity question it was more of the mating of the PVC pipe. Obviously you need the right approach angle so that the connection into the WYE is pitched properly to receive the 3" drain. With this elevation difference, if I just ran a straight run with no 45s or elevation compensation, you would have a drain pipe pitched so aggressively that it wouldnt mate up to the WYE. I was just wondering how a professional plumber calculates for, adjusts for, or considers this approach. Is a 3" WYE connection already pitched to receive a 1/4" every foot slope of pipe?

If you dont come at a connection clean on, it cant mate, that was my concern and wondering how people handle that.

 

[Reach4]

I was just wondering how a professional plumber calculates for, adjusts for, or considers this approach.

Re-read #2. I suggest you buy two 45s, or a 45 and a 22.5, and play with them. You will see that by making the axes (plural of axis-- I just looked it up) of the two to be not be the same, you can produce a wide range of angles.

To help visualize, you could buy two 1/2 inch street 45s, and play with those as models. You could sand one some so that you could fully insert it into the other and freely rotate. Expect to pay under $1 for each. Or to save a little money, make one a regular slip elbow, and get the pair for under $1 possibly.

For the real thing, you can also get 22.5 elbows in 3 and 4 inch. I don't think they have those in 1/2 inch for modeling....

 

[Alex S]

Reach thanks again sir!

I will have to see what you mean about the fittings. I think you are all correct and I am overthinking that connection. More wiggle room than I am imagining I guess.

Truly and honestly I know I ask some dumb questions on here, but the assistance and advice provided is incredible.

I can't thank you all enough. I should be shipping cases of beer out to all the people that have chimed in on my posts.

I got another dumb one coming right up! Stay tuned for Alex's idiotic question on a sink drain connecting to a toilet drain right under the flange.

 

[Plumber01]

Would you drop the closet elbow under the toilet a bit to allow the connection to make up?

Yes. Exactly. Measure elevation off of a point of reference to the wye, like the floor or ceiling. Add 3.5"(or subtract if measuring from above). That equals the elevation to the elbow under the toilet flange.