Hidden AAV?

[Chris Weekly]

Newer home with island sink counter. No AAV seen under the sink. I saw no unusual plumbing under the sink and only suspect an AAV was plumbed into the finished area within the wall cavity of the island.
I reported that this requires an accessible AAV, but can't find documents to back it up. Seems reasonable to me that this is required to be accessible. Also I would think that this may not operate correctly without an open air source to allow air to be drawn into the pipes. Can somebody back me up?... or is there another possibility?

[Jerry Peck]

I reported that this requires an accessible AAV, but can't find documents to back it up. Seems reasonable to me that this is required to be accessible. Also I would think that this may not operate correctly without an open air source to allow air to be drawn into the pipes. Can somebody back me up?... or is there another possibility?

You are absolutely correct on both counts: the AAV is required to be accessible and to be in a ventilated space.

However ... it is possible that they plumbed in a 'island vent', albeit many plumbers do that incorrectly - just that you would not see it unless there was a crawlspace or a basement under it.

Here is a drawing of an island vent: http://i44.photobucket.com/albums/f2/Redwood39/islandsinkvent.gif

[Chris Weekly]

Thanks for your reply Jerry. I go into an inspection thinking "Whats wrong here?" and write up what I see...or in this case what I don't see - the venting method for the drain. I have always seen the method under the sink, whether it is an island vent or AAV.
This was nicely done, but hiding the works within the wall cavity, still leaves me with "?"
No requirement to expose the island vent?...at least to reveal the method?

[Jerry Peck]

No requirement to expose the island vent?...at least to reveal the method?

No.

and

None, other than being on the approved plans.

[Chris Weekly]

Yeah, I guess the clause '...concealed from view...' within the contract should allow me to limit my suspicions.
But, I ... I ... i just can't leave well enough alone.

[Jerry Peck]

Yeah, I guess the clause '...concealed from view...' within the contract should allow me to limit my suspicions.
But, I ... I ... i just can't leave well enough alone.

One way to address it is to report that as:
- An island plumbing fixture was present, the vent was not visible/could not be verified - this does not mean there is no vent, nor does it mean that there is a vent, this only means the inspector could not locate or verify how it was vented, or if it was vented. Typically, the inspector finds an AAV installed for venting island plumbing fixtures, no AAV was found at this location.

All true statements.

[Joe Klampfer]

I go into an inspection thinking "Whats wrong here?" and write up what I see...

Did you write up the dishwasher drain tube being too low ? Also, whats plugged into the garburator receptacle, is that the dishwasher power connection ?

[Jerry Peck]

Additionally, the garbage disposer (food waster grinder) should not discharge into a drain that way with a tee fitting - the disposer will simply force the discharge across the tee and back up into the other sink if there is not enough height to overcome the force and let it go down into the drain and trap.

That should have had the trap turned over to the sink with the disposer entering the tailpiece through a downward directional fitting, or, better yet, trap the sink separately from the disposer and both traps enter the into a wye.

[Joe Klampfer]

Good one Jerry,

Also, with granite countertops, do you not require additional strapping for the double sink ?

[Jerry Peck]

Also, with granite countertops, do you not require additional strapping for the double sink ?

Joe,

I've only seen additional support a couple of times and am not aware of any requirement for it - that epoxy/sealant (whatever it is) is quite strong.

I've tested some really really deep double sinks/large single sinks by filling them with water to see if they fell or held, all held tight, no additional strapping.

I had one contractor who got the bright idea that he would put his arms under about a 40 gallon kitchen sink "in case it fell" ... as I was filling the sink, I explained that 40 gallons of water would weigh in about 330 pounds and does he think he can catch that or does he think it might just break both arms ... it took him about 30 seconds to consider the answer and then quickly pulled his arms back and stood up.:)

He said that if it falls, his countertop guy will have a bill to pay for all the work which might be needed - the sink held.

[Chris Weekly]

Did you write up the dishwasher drain tube being too low ? Also, whats plugged into the garburator receptacle, is that the dishwasher power connection ?

Yes, I did write up lack of air gap at the d/w drain.
The power plug for the d/w is the duplex receptacle with multi-wire connections - 1 circuit each to the disposal, and to the d/w.

The switch, of course, is for the disposal.

[Joe Klampfer]

Joe,

I've only seen additional support a couple of times and am not aware of any requirement for it - that epoxy/sealant (whatever it is) is quite strong.


Interesting, I'm not aware of a published requirement either but have never seen one installed without the added support.



Yes, I did write up lack of air gap at the d/w drain.
The power plug for the d/w is the duplex receptacle with multi-wire connections - 1 circuit each to the disposal, and to the d/w.

Great! Glad we're all on the same page

[Jerry Peck]

What makes you think it has an AAV?

Possibly because it was an island sink with no venting apparent?

[Jerry Peck]

My point is there is no way I would say it is a hidden AAV. Show a picture as to the 2 possibilities and go with that. No reason could I find would there be to put a hidden one in.

Guess you have just been unlucky enough to have been in an area where plumbers and contractors just don't do stupid things.

I *have* seen AAVs installed where there was no ventilation ... simply because I have seen the houses being constructed, no vent, stub up for what would obviously be an AAV, only to not have an AAV visible at my next inspection - my thoughts were WTH? Where did that AAV go?

Then, upon questioning, the contractor discloses that there was no room in the cabinet for the AAV with that large deep sink so ... they put the AAV in the wall and set the cabinet in front of it.

Not a real smart move, there.

You must be in one lucky area where the contractors actually understand what they are supposed to do ... and then actually do it.

[Chris Weekly]

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What makes you think it has an AAV?

because...I couldn't see if it had one or not. It might have one, it might not,...it might have some drain venting system, or not...and since I couldn't see what the method was....and since it was an island counter....I thought best to mention that I couldn't see what venting method was used.
What if (I'm thinking...) there were problems such as blocked drains (or gurgling noises), or something, and the new owners called in a plumber who said "Where's your vent?" The new owner said "my inspector didn't say anything about it not having a vent"....and then the plumber said...and the owner said...and then I get a phone call.....

I can't remember having never seen a method of venting. I've seen AAV systems under the sink. I've seen island venting under the sink. I've seen where sink vents are plumbed into walls and see their termination above the roof....but I've never seen no evidence of venting. It may not be wrong to conceal certain vent methods but it is going a bit too far for my liking to say nothing. So...I said something.

[Fred Weck]

There's is a wall built behind the cabinet that provides the space needed for the island vent and a cleanout underneath the trap arm that the island vent needs. If I was going to make an assumption that there is either an island vent or an AAV, I'd go with the island vent.

[Jerry Peck]

I have found both JP. No issues if you state both. Big issue if you search for a AAV but don't find it and state you can't find the AAV. When one was not needed. :(

May not be a problem.

Depends on how you state what you found/did not find/think you should have found.

- - - Updated - - -


There's is a wall built behind the cabinet that provides the space needed for the island vent and a cleanout underneath the trap arm that the island vent needs. If I was going to make an assumption that there is either an island vent or an AAV, I'd go with the island vent.

Why?

That wall allows for the plumbing for either ... with the AAV you would (should) see it.

What if you presumed that there was an island vent ... and there wasn't?

[Joe Klampfer]

What if (I'm thinking...) there were problems such as blocked drains...

No worries, the sink will simply drain (or siphon) down through the dishwasher. That's why its important to ensure the DW drain line routes up & over the sink's high-water level.