Air Admittance Valve (AAV)

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Old 10-01-06, 01:19 PM
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Question Air Admittance Valve (AAV)

Do they go by any other name? I was in two hardware stores and asked if they had auto-vents and they had no idea what I was talking about.

When and where is the appropriate place to use them?

Thanks.
 
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Old 10-01-06, 01:52 PM
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You may be referring to an AAV, or Air Admittance Valve
 
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Old 10-01-06, 08:33 PM
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AKA

Cheater Vent, Pro-Vent, Trailer Popper.


It's a device used in some areas that allow them. In Kentucky they are not allowed and other states as well. It is a diaphragm device that allows air to enter into the plumbing DWV system but not allow sewer gases to escape.

It is a mechanical device that works off of a tempered spring and rubber disk that over time wears out. Check with your local codes to find out if they are legal for use in your area.
 
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Old 10-02-06, 12:01 PM
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Also a Studor vent.

You just may not be able to buy them locally as it isn't allowed under your code.

Good luck...
 
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Old 10-02-06, 08:40 PM
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I see that they are also called "air admittance valves" (AAV). I was doing some reading on the 'net and some areas of the country use them completely as replacements for roof vents.

I understand that AAVs are one-way valves that only allow air to enter the plumbing system. Don't roof vents also allow air to escape the plumbing system? If so, how could a one-way AAV accomplish the same thing?

Thanks.
 
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Old 10-03-06, 07:10 AM
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The purpose and design of plumbing vents is to allow air to enter "into" the system rather than exit it - allowing pipes to drain after plumbing traps by equalizing the pressure in the pipes after the traps (like taking your finger off the upper end of a plastic straw filled with liquid - the liquid drains out quickly). Obviously some air/sewer gasses will waft out of the pipes during a static condition - but that is incidental to their purpose.
 
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Old 10-03-06, 10:14 AM
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Two questions:

1) Why do I and many other people I've talked to have a strong odor that comes out of the pipes when plumbing is used (running water from sinks and tubs and flushing toilets)?

2) How does air escape from plumbing in homes that exclusively use AAVs ?

Thanks.
 
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Old 10-03-06, 11:51 AM
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An improperly vented drain will cause negative pressure infront of the water trap that sucks the water right out of the trap allowing sewer gas from the system thru.

Think of it like the pipe draining the water gets full. The water is going down hill creating a vacuum behind it. If there is no vent for the air to come into then it will pull water from the trap. When it depletes the trap it pulls as much air as it needs to drain. This causes the water in the pipe will run much faster down the pipe and not use the whole pipe (the top of the pipe will have an air gap). The air gap is full of sewer gas from further down the line and it travels up, opposite the water thru the depleted trap and into your nose.

AAV’s look good on paper but after 15 years or so their seals break down, springs break, and they stop sealing properly. Basically they stop working right because they are mechanic and everything mechanical eventually breaks unlike a proper vent system that has no moving parts.
 
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Old 10-03-06, 04:17 PM
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I've never seen a home totally done with AAV's - but rather in places otherwise inaccessable to a vent system (island sinks, for instance). In those situations, the AAV is readily accessible for replacement when necessary.
 
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Old 10-03-06, 07:57 PM
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Do you think I can use an AAV to supplement my existing vents?
 
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Old 10-04-06, 09:02 AM
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Yes, unless your local code prohibits them
 
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Old 10-04-06, 09:51 AM
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AAVs

Originally Posted by iowa
Do they go by any other name? I was in two hardware stores and asked if they had auto-vents and they had no idea what I was talking about.

When and where is the appropriate place to use them?

Thanks.
They are also called Quick-Vents.

If I could run a REAL vent I would not use them at all!

They do go bad.

Like the other posts said, they might be against code.


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"If all else fails, read the directions"
 
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Old 10-05-06, 06:48 AM
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Originally Posted by iowa
Two questions:

1) Why do I and many other people I've talked to have a strong odor that comes out of the pipes when plumbing is used (running water from sinks and tubs and flushing toilets)?

2) How does air escape from plumbing in homes that exclusively use AAVs ?

Thanks.
AAV's are allowed only on systems that have at least one atmospheric vent. This atmosheric vent must be the same size as the building sewer. There is also a requirement for multi-atmospheric vents that equal or exceed the cross diameter of the building sewer. You would not have to worry too much about this in a residental setting.

IF AAV's are allowed in your drains, then, this other requirement must be met. It is a code thing.

Good luck with your project...
 
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