[arky217]

Which of these is the best configuration for a toilet drain ?

Going to assume that C is incorrect because of no immediate vent pipe; that leaves A or B.
Which one would be the best configuration ?

Thanks,
Arky

[leonandlisa]

B is the best.

Leon

[johnjh2o]

A is the best. Using a Y is always better then a sanitary tee.

john

[arky217]

I've posted this on several other forums and so far, the B's have outnumbered the A's.

The A proponents mostly say that it's a straighter shot, thus less chance of clogs.

The B proponents say that the A allows too much rush of water, thus restricting the vent.

I'm still 'up in the air' about which one to go with, but, not being a plumber,
if left to my own impression, I would probably have chosen A.

Anyone have a strong argument for either ?

Thanks,
Arky

[stevemachine]

I agree with A, and John. A wye is way better than a t wye. However you have to remember that the fall of the pipe shouldn't be more than one pipe diameter before it reachs it's vent. I say Pipe it like B but then use a wye and fitting 45 instead of a t wye. Just my two cents though.

[phishfood]

Actually, under 2007 and later International Plumbing Code, there is no distance to vent limitations on a self siphoning fixture such as a water closet, since the fixture is designed to siphon the trap, and is designed with a means to refill the trap afterwords.

So I would vote for A as well.

[stevemachine]

Touché phish. I see your point. I guess what I've learnt according to our code was that you couldn't have the fall exceed the one pipe diameter, we cant do it in my region from my knowledge, but it totally makes sense what your saying.

[PioneerPlumber]

Definitely A. However, my first thought would be that you're now at a deeper elevation thus requiring a deeper excavation. Because **** runs downhill, the remaining portion of the downstream system will now be progressively deeper.

If fall is not an issue, install like "A". Regardless of what the traditionally or most common application is, A is better.

Put a full size clean out above grade to allow for future snaking with a full size head. 3" piping/3" clean out, etc.

And pardon my French. I'm a Plumber :-)

[arky217]

In the following picture, assuming that the 'other drainage' pipe cannot be moved, which would be the better arrangement, A or B ?

Thanks,
Arky

[stevemachine]

B in my opinion. Especially if the other plumbing is vented through the stack. Toilet needs to be the lowest connected fixture on a wet vent.