Toilet Fitting - Drain/Vent Question A really bad example

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Patrick R Wunsch

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Would the below pictured fitting work as described in the pic?

It's a dedicated 3" toilet drain entering the left side of the fitting. The right side would reduce to a 2" vent that turns upwards well under 6' from the toilet drain. The bottom empties into the main stack.

I'm really limited on other options as the toilet drain runs just under the floor, parallel with a joist and needs to stay within the 2x8 joist bay until it can dump down in a utility room. This toilet drain run is not under the plumbing wall which is in the next joist bay behind this one so I'd like to stay away from flat venting and cutting holes in the joist

This group has been an awesome resource and I appreciate any input.

Screenshot_20220823-112142_Chrome.jpg
 
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Patrick R Wunsch

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Would the below pictured fitting work as described in the pic?

It's a dedicated 3" toilet drain entering the left side of the fitting. The right side would reduce to a 2" vent that turns upwards well under 6' from the toilet drain. The bottom empties into the main stack.

I'm really limited on other options as the toilet drain runs just under the floor, parallel with a joist and needs to stay within the 2x8 joist bay until it can dump down in a utility room. This toilet drain run is not under the plumbing wall which is in the next joist bay behind this one so I'd like to stay away from flat venting and cutting holes in the joist

This group has been an awesome resource and I appreciate any input.
Or would this be more appropriate for the intended use?

Screenshot_20220823-121258_Chrome.jpg
 
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wwhitney

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No, your 2" vent would be a horizontal takeoff. A dry vent needs a vertical takeoff and to stay vertical until at least 6" above the fixture flood rim. Vertical includes up to 45 degrees off plumb.

Often WC venting is accomplished via wet venting. For dry venting, you can take a vent off a vertical section of the WC drain with a wye, and rise at a 45 degree angle until you're under the vent wall. Unlike fixtures with external traps, the elevation of the vent takeoff on a WC is not restricted.

Cheers, Wayne
 

Terry

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If you look at the instructions that come with toilets, you will realize the the water and waste will skip right over some fittings.
Your "vent" would be clogged with poo in no time.


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Patrick R Wunsch

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If you look at the instructions that come with toilets, you will realize the the water and waste will skip right over some fittings.
Your "vent" would be clogged with poo in no time.


back_to_back.jpg
Thanks Terry. Given what wwhitney wrote above about horizontal takeoffs, I'm assuming I still wouldn't be able to use the double combination wye you described by me still running a horizontal vent about 20" from the right side of the wye prior to it turning straight up? (I'd have to cap the center outlet as that would be just below the subfloor).
 

wwhitney

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a horizontal vent about 20"
Nope. But if you are able to drop your (single) wye 20", then you can get traverse 20" horizontally while rising 20" at a 45 degree angle.

If the above is not feasible, how about a sketch of the entire bathroom DWV? There may be other venting possibilities you haven't considered.

Cheers, Wayne
 

Patrick R Wunsch

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Nope. But if you are able to drop your (single) wye 20", then you can get traverse 20" horizontally while rising 20" at a 45 degree angle.

If the above is not feasible, how about a sketch of the entire bathroom DWV? There may be other venting possibilities you haven't considered.

Cheers, Wayne
I appreciate your patience! So are you saying I could vent out with a 3x3x2 wye along any portion of the stack as long as its within 6' of the fixture? (In another words, the vent doesnt have to T off the horizontal drain, it can T off the vertical stack provided it meets the 45 degree or less criteria). If so, I may have another option I didn't think of. I appreciate your time!
 

wwhitney

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I appreciate your patience! So are you saying I could vent out with a 3x3x2 wye along any portion of the stack as long as its within 6' of the fixture? (In another words, the vent doesnt have to T off the horizontal drain, it can T off the vertical stack provided it meets the 45 degree or less criteria).
Yes, see the last sentence of my first post.

However, if you are dry venting your WC via a vent takeoff on the stack, that only works if the stack is only carrying the WC drainage at the point of the vent takeoff. Because the WC dry vent has to come off before the WC fixture drain joins any other drains. But since your example fittings don't include an upward connection, I take it the WC is coming in to the top of the stack.

Now if the WC is entering at the top of the stack, and another dry vented bathroom fixture is joining the stack within the 6' distance limit from the closet flange, that bathroom fixture may be able to wet vent the WC. A full diagram of the bathroom DWV would be required to be sure.

Cheers, Wayne
 
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Patrick R Wunsch

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Yes, see the last sentence of my first post.

However, if you are dry venting your WC via a vent takeoff on the stack, that only works if the stack is only carrying the WC drainage at the point of the vent takeoff. Because the WC dry vent has to come off before the WC fixture drain joins any other drains. But since your example fittings don't include an upward connection, I take it the WC is coming in to the top of the stack.

Now if the WC is entering at the top of the stack, and another dry vented bathroom fixture is joining the stack within the 6' distance limit from the closet flange, that bathroom fixture may be able to wet vent the WC. A full diagram of the bathroom DWV would be required to be sure.

Cheers, Wayne
Great, I'm following you so far but just to double check my understanding... where the toilet enters the stack will be the upper most drain entering that stack. I will have a 2" drain entering the same stack but BELOW where the toilet enters. That 2" drain (laundry stand pipe, shower & lav) is vented separately from the toilet's vent. Does this sound alright? Again, thanks so much!
 

Terry

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A bathroom wet vent would be allowed to vent the toilet. That would be the lav and the shower.
The washer comes in downstream with it's own venting, which can tie back into other vents above the flood level of fixtures served.
 

wwhitney

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Great, I'm following you so far but just to double check my understanding... where the toilet enters the stack will be the upper most drain entering that stack. I will have a 2" drain entering the same stack but BELOW where the toilet enters. That 2" drain (laundry stand pipe, shower & lav) is vented separately from the toilet's vent. Does this sound alright? Again, thanks so much!
So, since the next drain coming in below the WC isn't just bathroom fixtures (it includes the laundry), it can't be used to wet vent the WC. But you can take a dry vent off the stack above that 2" drain, and that can dry vent the WC, if it's within the 6' along the pipe limit from the closet flange (I infer since you brought up that limit NE uses the UPC).

Cheers, Wayne

Edit: or, as Terry suggests, if you separated the laundry from the shower/lav, with the shower/lav hitting the stack as the next drain below the WC, and the laundry coming in below that, it would be possible for the shower/lav to wet vent the WC. But a diagram of the whole thing would be best to confirm everything is correct.
 

Patrick R Wunsch

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So, since the next drain coming in below the WC isn't just bathroom fixtures (it includes the laundry), it can't be used to wet vent the WC. But you can take a dry vent off the stack above that 2" drain, and that can dry vent the WC, if it's within the 6' along the pipe limit from the closet flange (I infer since you brought up that limit NE uses the UPC).

Cheers, Wayne

Edit: or, as Terry suggests, if you separated the laundry from the shower/lav, with the shower/lav hitting the stack as the next drain below the WC, and the laundry coming in below that, it would be possible for the shower/lav to wet vent the WC. But a diagram of the whole thing would be best to confirm everything is correct.
Thanks. I think where you write

"But you can take a dry vent off the stack above that 2" drain,..."

Is my best option as it will be my a dedicated dry vent for the WC and less than 3' away from the flange. I should be able to draw something up later just to confirm but I'm pretty sure I'm following. Thanks guys!
 
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