Studor Mini-vent relocation?


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Old 01-12-14, 01:29 PM
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Studor Mini-vent relocation?

Currently, this is what the plumbing looks like under the kitchen sink. The pipe marked in red goes up to a Studor Mini-Vent that is as far up as it can go behind the left sink basin.

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I am wanting to get the counter replaced (granite with undermount sink). The problem is that I don’t think there will be enough room back there when I change to an undermount sink. From my calculations, the average dimension of undermount sinks are about 18-20” (external), countertops 24”, and the mini-vent is about 3” in diameter. As it is right now, with the topmount sink, there is just enough clearance to unscrew it in case it needs to be replaced. So, I am thinking that I probably want to relocate it. From my initial research, it appears that it is fine as long as it is 4” above the p trap. However, I’m confused because some places seem to indicate you want it up as high as possible. It seems whoever installed this wanted it as high above the sink as possible. What problems will I have if I change the configuration to something like this? Is this even possible?

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Note 1: I know I should get a high loop on the Dishwasher return to the garbage disposal. I plan on doing that when I replace the dishwasher.

Note 2: Currently, Studor Mini-Vent is in an upright position. The pipe slant, then go up vertically. I figured someone might make a comment on this.

Note 3: This does not appear to be a vent stack system. It is a single story house, and looking under all other plumbing, it appears it is the only place with a Studor Mini-Vent. The rest of the house appears to be on a standard vent to the roof (I have two on the roof, presumably for the two bathrooms).

Note 4: This is in Tennessee in case anyone is curious for coding purposes.
 
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Old 01-12-14, 02:47 PM
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I'm not crazy about your overall plumbing set up. I don't think you can bring two drains into a "T" like you have. The trap should be below the left sink and the disposal should feed into the tube directly above the trap.

My understanding of air admittance valves is that they are not allowed to have a bend in the line (at least I got dinged on an island setup for trying to do as you did).

Will you have a single or double under mount sink? Cabinets are 24", the counter top will be closer to 26" as it needs to span the cabinet, span the doors on the cabinets and still overhang those by 3/4" to 1". The tendency is to go over sized with the under mount sink (incl. depth). That is where you will run into trouble. My guess is that you will have plenty of room once all is said and done.
 
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Old 01-12-14, 03:35 PM
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Thanks for the quick replies.

That document was one of the things I read. I am not adept at reading the technical language and this was one of the issues I got confused with. On page 17, it says "1. in single fixture and branch applications the Studor AAV shall be located a minimum of four (4) inches above the weir of the fixture trap." But I am confused at the part where it says "7. The stack type Studor AAVs shall be installed six (6) inches above the highest flood level rim of the fixtures being vented in stack applications." Since (I believe) this is not a stack, I don't need to be 6 inches above the sink?

What do you mean about not being able to use a T like this? Do you mean because the T on one side uses a garbage disposal? From what I understand you're saying, the garbage disposal should T into the left sink pipe, and then down into the P trap. This would cause the the entire piping assembly to shift down a little bit, which may actually work in my favor. If the only requirement for the AAV is to be 4" above the weir, I would have plenty of clearance.

In your island configuration, did you have your AAV just 4" above the weir, or did you have to have it above the sink level? That's really mostly what I'm worried about. If the only requirement is to have it above 4" above the weir, and not above sink level, I can probably manage to fit everything. My only hesitation is that the bends in the piping to the AAV (as you pointed out) seem like it took extra work from the previous owner/plumber. They could have easily just went up 4" but the fact that they took the extra work like that is contributing to my confusion to the requirements of an AAV.

In summary, is the proper fix here is to do the proper T as pointed out, shift the rest of the piping assembly down to accommodate, and then install the AAV 4" above the weir?

Also, on a side-note, I keep seeing all these things about an air gap, which appears to be for a dishwasher. I obviously don't have one, and was wondering if this was necessary.
 
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Old 01-12-14, 03:53 PM
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Here is a closer visual of what I was trying to describe.

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Old 01-12-14, 04:05 PM
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I don't think you can bring two drains into a "T" like you have.
Yes thats fine... The is a center waste tee...


I keep seeing all these things about an air gap, which appears to be for a dishwasher. I obviously don't have one, and was wondering if this was necessary.
Not needed by code... Just loop the hose up in a high loop under the sink per manufacturers instructions..


My understanding of air admittance valves is that they are not allowed to have a bend in the line
The actual AAV is most likely vertical... Thats fine...
 
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Old 01-12-14, 04:51 PM
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Ok so it looks like what I want to do do accommodate the undermount sink/countertop is ok.

Just our of curiosity any thoughts on why it looks like someone went through extra trouble to get the AAV that way... Up as high as possible with the bends and such...
 
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Old 01-12-14, 05:47 PM
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Its supposed to go as hi as possible...

And I would noy put the studor on the horizontal as you show... It should be out a tee as you have now...

Technically they should be above the flood plain of the sink... IMO not below the drain or strainer...
 
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Old 01-13-14, 04:42 AM
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I agree with Mike (and Z). I don't see a problem with the angle as long as the Studor is vertical. IMO it ain't broke, don't fix it.
 
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Old 01-13-14, 04:53 AM
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Ah, ok. I will install it at the T, as high as I can go with the new sink. Hopefully, I will have enough room that it's higher than drain/strainer.

If I'm still missing something, let me know. Thanks for all your help.
 
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Old 01-17-14, 06:56 PM
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So I'm still a little confused. Am it supposed to used a wye or sanitary tee or some other type of connection for the Studor, p trap, waste line intersection? Also do I just use PVC schedule 40 for all of this? I also read that I shouldn't use any glued joints for this... Is this right?
 
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Old 01-18-14, 11:00 AM
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Bump... please help with the questions above.
 
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Old 01-18-14, 11:41 AM
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See post #8 and others.........
 
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Old 01-18-14, 01:41 PM
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I'm not following how #8 solves my issue. I can't leave it as is because I won't have enough room for the studor where it is now when I put a new sink. And I have no idea what i have now... Wye, sanitary tee, etc. it all looks the same to me.
 
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Old 01-18-14, 01:47 PM
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Why are you not doing it like this again?.

This is the correct way...

[ATTACH=CONFIG]25000[/ATTACH]
 
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Old 01-18-14, 06:47 PM
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The new sink is going to be deeper and probably not the same distance between basins. There is a good chance I will need to change something down there so I was wanting to make sure I do it right. Also, I thought it would be easier to just start from scratch instead of reusing what's down there.
 
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Old 01-18-14, 07:03 PM
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Am it supposed to used a wye or sanitary tee or some other type of connection for the Studor, p trap, waste line intersection?
A san-tee is a bit smaller and will do what you need. You can use a combo wye (wye with a street 45), but it's a bit larger and not necessary.

Also do I just use PVC schedule 40 for all of this?
Most of it will need to be cemented PVC since slip couplings don't come in all those different -fittings. Keeping the p-trap section slip fittings will help if you ever get anything stuck or need to snake it. No code issue either way though - just stay away from those flexi-hoses.
 
 

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