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Discussion Starter · #1 ·
I had went to NJ and saw my dad on a plumbing job and he asked me how to do an island sink drain. I told him we run a whatever the main line x 2" tee wey, then come up through the floor, through the cabinet base, install a sanitary tee with a AAV on top of the tee. I helped him do it and when the inspector came he failed it. Not because we used a mobile home vent, we used a top of the line brand (Cant think of it right now) but rather the inspector wanted a what ever x 2" tee wey on the main line, then come up into the cabinet, then turn a 90, over to a 2x2x1-1/2 sanitary tee on its side so the trap can connect to the 1-1/2 side, then the other side the tee goes over to another 90 turned down, then run back through the cabinet to the main, connected by another what ever x 2 tee wey. I cant for the life of me figure that one out because what you are trying to accomplish is actually a vacume break. If the main line loads up as it passes the sink it causes negitive pressure in the line to the sink (Vacume) thus sucking the water out the trap. So, where happens when the main line loads up with this inspectors idea? There is no place for air to get in to break the vacume at all exept through the trap. Am I missing something here?

Dont laugh at my drawing, I am not an arist:rolleyes: but this is how the inspector wanted it. The red dot is the tee for to catch the sink trap
 

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He had the right idea with how he wanted it, but he missed one thing.When we install an island sink we come through the cabinet twice. Downstream we cut in a vent and arm it over to the nearest wall. Lay combos down, and on the second drain line we cut in a 2" combo to hit the wall. Now its vented....Studor vents are not legal down here unfortunatly..
 

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Plumber Manhattan Beach
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AAV's are not legal here, unless you can talk the inspector into it. Except you need a c/o on the vent in the wall, and where the santee is, you should use a comby, but sometimes you don't have the room, so the inspector will approve the santee.

Maybe this will help, this is legal, in UPC country.
 

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AAV's are not legal here, unless you can talk the inspector into it. Except you need a c/o on the vent in the wall, and where the santee is, you should use a comby, but sometimes you don't have the room, so the inspector will approve the santee.

Maybe this will help, this is legal, in UPC country.
You mean a combo where the vent tees off? Why so?

BTW, this is the way I am used to doing it pre-AAV.
 

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Discussion Starter · #6 ·
OK, now here is the problem people! code clearly states "No vent line shall run horizontal unless it is 6" or more above the flood rim level" So according to that pix it is a code violation. So they are violating it themselves by wanting it done that way.
 

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You mean a combo where the vent tees off? Why so?

BTW, this is the way I am used to doing it pre-AAV.


Not sure, supposed to be a comby where the vent goes to the wall.. This is how it is in the UPC illustrated manuel. shows a wye 1/8th bend.
 

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OK, now here is the problem people! code clearly states "No vent line shall run horizontal unless it is 6" or more above the flood rim level" So according to that pix it is a code violation. So they are violating it themselves by wanting it done that way.
My code does not say that, it says all vents must tie in 6" above the flood rim of the tallest fixture being served by said vent.
 

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Right, to can run a vent below the flood level rim, but rules do apply, vertical to horizontal can be a short turn, but when going from horizontal to vertical it has to be a drainage fitting, then when connecting to the exiting vents, you have to be six inches above the the fixture it surves as KTS just said.

UPC Code.

That island loop picture posted by WCP is correct, except you have to have a clean out on the vent in the wall and it has to be accessible.
 

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Discussion Starter · #11 ·
Why the high loop above the sanitary tee at the trap? Cant it be lower, or is that the thing to do, extend the "Loop" as high up under the sink top as you can get it to go?
 

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Why the high loop above the sanitary tee at the trap? Cant it be lower, or is that the thing to do, extend the "Loop" as high up under the sink top as you can get it to go?
You want to extend the vent as high in the cabinet as you can to prevent waste from entering the vent in case of a blockage.
 

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J. McCabe Plumbing Inc.
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905.3 ...... Vents less than six(6)
inches(152mm) above the flood-level rim of the
fixture shall be installed with approved drainage
fittings, material, and grade to the drain.


You allready mentioned the requirement for a cleanout on the vertical vent riser but I noticed that medium sweep 90 on the vent just before it rises vertical.

A code violation according to the UPC and inforced in my area.
 

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Not sure why it's not showing in my code, but it used to say type of fitting you can use on change of directions, all I know is how it's been done, and it's still being done today. So yes in reality it's not being done to code, I'll ask next time I see an inspector.
 

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For the record, the picture was for reference, it may or may not be code in your area. we have to do our island vents this way, except for the couple things i mentioned in my original post about the cleanout in the wall, on the vent, and the santee being a wye 1/8th.

this picture gave a good example, except for the few code changes that need to be done. :yes:
 

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Here we can just stub up an 2" line through the bottom of the cabinet. In certian county's there are different rules. every county allows us to stub up 2" bu tin one county we have to install studer vent. in other countys put a 2" 90 with 2x 1 1/2 bushing in it. Code can be taken in so many different ways.

Here is a code that is quite broken here. In my Code book Table 7-5 DFU's chart it show that on a horizontial 1 1/2 can only have 1 dfu how many dfu's is a tub/shower unit??? According to my book it's 3 units SO how does this pass? :blink: There is another situation but I can't remember it right now.
 

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Discussion Starter · #18 · (Edited)
According to my book it's 3 units SO how does this pass? :blink: There is another situation but I can't remember it right now.
I always thought that any floor drain shall not be less than 2", so if a shower is considered a floor drain then it should have to be 2" waste line. AND I thought the code also says you can not reduce the size of the drain going downhill, and most showers I install have a 2" drain, so that means one would have to install a 2x1-1/2 flush bushing or reducer coupling, thus reducing the size as it flows downhill. And a tub/shower combo is a tub so to speak so the 2" rule does not apply to the tub. But then again, there is much more volume of water coming out of a tub than a shower, so I would had thought the tub should have a 2" drain. betcha the water would run out real quick that way!
 

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USP, you're diagram with the red dot shows a san tee connecting to the vertical portion of the bow, I think your inspector is on drugs buddy!:no:

Robert / Westcoast's picture is a great display of a good bow vent / island sink.

As for the vent, we have to use combo's on all vents vertically connecting to a horizontal run.

A good way to look at it is if a small twig just long enough to not make the radius of a shortsweep falls into the external VTR, it will stop and rest in the horizontal run...leading to a clog.
It could also happen on a combo, but at least a combo gives a wider radius.
 

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I understand a combo for any vent connecting to a horizontal drain.

What I don't understand is a combo for a horizontal vent connecting to a vertical line. In fact, I think it's dead wrong.

A san-tee in the vertical position is definitely a drainage fitting just as a regular 90 is when used from horizontal flowing into a vertical pipe.

What am I missing guys?
 
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