# Got a Studor AAV valve still a question about height!



## petros151 (Jan 10, 2012)

Finally got a Studor min AAV and am reading the info....

The Studor on line spec sheet for this mini-AAV says to put it minimum 4" above the* trap* for a single fixture and the reference to 6" above the flood level of the highest fixture is when it's in a stack vent application.

I am still wondering about being able to put this under a sink cabinet as high as it can go which is about 7" above the trap. Aren't these things designed to resist backflow? They admit air when getting suction down away from the valve but then they close so any sewer gas pressure going up into the valve locks the thing shut. So how could it leak if the sink backed up? I would think any water getting forced up into the AAV would keep it shut? huh? :confused1:


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## TheEplumber (Jul 20, 2010)

Put it under the the sink as high as possible- off the top of your tee. They are a 1 way valve but anything mech. is bound to fail at some point.


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## Javiles (Dec 12, 2011)

They will leak in the event of a back up, unless installed above the flood line of the service fixture.


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## Alan (Apr 12, 2006)

What they are referring to is if you're using it for a single fixture, you can put it on the trap arm a minimum of 4" above the flood rim. I put them as high as I can while still being accessible without having to work behind the kitchen sink.

The other situation they are describing is when you are using it for multiple fixtures or a bathroom group. You can't vent the whole bathroom group under the cabinet of the lavatory. 6" above the flood level rim is the minimum in that instance.


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## petros151 (Jan 10, 2012)

not to beat a dead horse but this is still unclear and for anyone searching results about AAV in this I want to try to get a clear answer for us all

The Studor .pdf info says "the mini-vent should be located a minimum if 4" above the WEIR of the fixture trap for a single fixture and branch venting..."

so I looked up weir and it is (they say) the bottom level of the horizontal pipe that goes into the wall on a sink drain.

so the Studor site seems to me is saying that for a sink you can put the AAV under the cabinet as long as it is 4" or more above the bottom of the horizontal pipe coming after the P trap.

I can't see what else it means. I blew into the AAV and it did lock tight so again I cannot understand how if water was to push against the AAV it would leak, BUT maybe it is designed to close on air pressure but water would make it act differently?

I am going to call Studor and post their reply. :whistling2:

thanks everyone


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## TheEplumber (Jul 20, 2010)

petros151 said:


> not to beat a dead horse but this is still unclear and for anyone searching results about AAV in this I want to try to get a clear answer for us all
> 
> The Studor .pdf info says "the mini-vent should be located a minimum if 4" above the WEIR of the fixture trap for a single fixture and branch venting..."
> 
> ...


Take a look here http://www.studor.com/DesignCriteria.pdf


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## Alan (Apr 12, 2006)

petros151 said:


> not to beat a dead horse but this is still unclear
> ....
> .....
> so the Studor site seems to me is saying that for a sink you can put the AAV under the cabinet as long as it is 4" or more above the bottom of the horizontal pipe coming after the P trap.


Yes .


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## Javiles (Dec 12, 2011)

petros151 said:


> not to beat a dead horse but this is still unclear and for anyone searching results about AAV in this I want to try to get a clear answer for us all
> 
> The Studor .pdf info says "the mini-vent should be located a minimum if 4" above the WEIR of the fixture trap for a single fixture and branch venting..."
> 
> ...


 
Let’s beat a dead horse; you can put that valve on the horizontal or the vertical under that sink recommended 4 inches above the horizontal level of the waste arm. As long as it’s not s trapped there should be a minimum of 12 inches from the trap to the vertical drop, hard to do under a small cabinet area. And they will leak seen it a million times. And eventually leak gas in to the building, that why they must be installed for easy access they will at some point need to be replaced. You can vent a complete branch with that one AAV. Don’t like them. I’d rather use a vent loop seemed to work well for many years.


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## petros151 (Jan 10, 2012)

ok thanks for the reply. The problem is I cannot tie into any vent stack because there is none for the 1st floor (100 yr old house) all the diagrams for loop vents show somewhere it getting tied into a vent. Do you have any diagrams that show a loop vent not tied into a vent stack?

here's one typical that I found. would it work if there was no pipe running to that vent source?


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## Alan (Apr 12, 2006)

petros151 said:


> ok thanks for the reply. The problem is I cannot tie into any vent stack because there is none for the 1st floor (100 yr old house) all the diagrams for loop vents show somewhere it getting tied into a vent. Do you have any diagrams that show a loop vent not tied into a vent stack?
> 
> here's one typical that I found. would it work if there was no pipe running to that vent source?


The whole point of a loop vent is tying it in to another vent, or venting it through the roof. No, it won't work if you don't vent it in some manner.


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## petros151 (Jan 10, 2012)

Alan said:


> The whole point of a loop vent is tying it in to another vent, or venting it through the roof. No, it won't work if you don't vent it in some manner.


ok thanks. NOW the vent problem near the sink can't be solved no way to run something up to roof (old house) BUT there is a place where I can run a vent inside the house in a chase then into the attic and thru the roof

here is a schematic of basic outlay of a future plan where a toilet and washer standpipe will be installed. 

So if I was to run this new vent now if I was able to connect my loop vent for the sink to this vent even though it will be 24 feet away will that work? 

if not then I'm back to using the AAV


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## Alan (Apr 12, 2006)

petros151 said:


> ok thanks. NOW the vent problem near the sink can't be solved no way to run something up to roof (old house) BUT there is a place where I can run a vent inside the house in a chase then into the attic and thru the roof
> 
> here is a schematic of basic outlay of a future plan where a toilet and washer standpipe will be installed.
> 
> ...



You have to have enough room under the house to run the auxiliary vent line back to whatever wall that is and have it ON GRADE at 1/4" per foot back toward the drain.

If it was close and you had say only room for 1/8" per foot, i'd say go for it, it's probably still better than a studor vent.

So you need 6" . . . . you could fudge it with only 3 ".......... Any less than 3" and i'd put in a studor vent, or find a closer wall.....


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## petros151 (Jan 10, 2012)

OK so you're saying the horizontal vent connection from the sink drain area has to slope UP to where the connection to the vent stack will occur right? so gasses can move more easily up to the vent. if I have that part right then This might be possible and if not 6" I think I could get at least 4 maybe 4.5" for that 24 foot run...

I'm going to take a few days to do more research and map out the whole thing with all fixtures and then post it see if I got it right but this looks promising.

many thanks for the help! :thumbup:


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## petros151 (Jan 10, 2012)

petros151 said:


> I am going to call Studor and post their reply. :whistling2:
> 
> thanks everyone


I called Studor- very interesting I think. first the secretary said "oh good morning what can I do for y'all" I told her I was a home owner and she gave me the CELL number of the USA tech person, and I called him his name is PAT he answered and was willing to answer questions for 20 min. very impressive me being a single vent user and not an industrial customer. 

Here's scoop.

First off he said if people refer to an AAV and they are meaning the little black pro vents you get with the spring loaded mechanism he said yes those will fail quick.

Taking into account he is a rep for the company, he said this: you can use a Studor mini-vent in a sink application and have it under the counter as long as it is at least 4" above the weir of the drain.

I said openly there are people who are saying if there is a back up the thing will leak.

He said again if it is a Studor vent it will not leak. He said they test these vents to 30" water column pressure that is what they claim and in fact they actually privately test them to 5 PSI which he said was more like 10 feet of water column

He said if there is at least 4" of air (ie. the 4" above the weir) then if there is a backup the water is going to push that air against the valve and shut it. And unless you have a 5 PSI against the valve it is not going to leak and he said what will happen is your sink will over flow not the valve leak.

Not that this is a perfect situation ie. you would get water from the sink backing up but he claims that a Studor vent will never leak in a sink application because of a sink back up. 

Interestingly he said as far as durability they use Studor vents in many sports stadiums like Olympic stadium Phillips arena Detroit Lions etc.. and they do not fail in that demanding application. 

He sited the fact that for instance in my state PA they are allowed and in N Carolina they got ok'd in 1992 and there have been no attempts to repeal the ok due to failure problems on any large scale.

He said that in fact if one fails a home owner can get a replacement for free and there are millions of them in the US that are in operation.

Again he said this only applies to Studor vents not pro vents.

I wonder if those who have seens AAV vents leak could specify if they were Studor ? 

I hope this helps anyone interested and also opens it up to counter claims from p;lumbers. 

I'm pretty convinced it will work BUT I'm going to hedge my bet any way and plan out a way to tie into a vent in the future if needed. take it away plumbers! :boxing:


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## Alan (Apr 12, 2006)

I don't really understand the way he referenced the AAV versus STUDOR argument. 

An AAV is an air admittance valve.


Studor is a brand of air admittance valve.


The relationship really goes no further than that. I've heard the same things that he was touting to you over the phone, but in our code, it's an alternate method, which to me says : If there is no other way of doing it, then it's allowable.


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## petros151 (Jan 10, 2012)

Alan said:


> I don't really understand the way he referenced the AAV versus STUDOR argument.
> 
> An AAV is an air admittance valve.
> 
> ...


he was saying those Pro Vents at HD are also called AAV they are cheap little plastic housing with a spring mechanism and the Studor also is an AAV but it does not work with any mechanical parts to wear out. I think it is like a piston sliding in a cylinder housing so that's the differentiation he said he believes some plumbers use AAV to describe any AAV but my questions is for those that say the see AAV's leak "all the time" are these black pro vents or Studor brand AAV vents usually mini-vents. If anyone has had Studor mini-vents fail "all the time" I'd hope you'd post about it. thanks


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## TheEplumber (Jul 20, 2010)

petros151 said:


> he was saying those Pro Vents at HD are also called AAV they are cheap little plastic housing with a spring mechanism and the Studor also is an AAV but it does not work with any mechanical parts to wear out. I think it is like a piston sliding in a cylinder housing so that's the differentiation he said he believes some plumbers use AAV to describe any AAV but my questions is for those that say the see AAV's leak "all the time" are these black pro vents or Studor brand AAV vents usually mini-vents. If anyone has had Studor mini-vents fail "all the time" I'd hope you'd post about it. thanks


I can't answer that because only recently(less then a year) have AAV's, a code definition, been allowed in my state. 
And it's only under certain conditions. 
And it's subject to the AHJ's approval. 
And it must carry a UPC approval stamp.


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