Pros and Cons of Using AAVs

Hi All:

After reading many of these threads about venting, it sounds like there is never a bad time to use an AAV to vent a fixture. It also seems more cost effective to use AAVs instead of having to route pipe all the way to the roof?

When or why would you not want to use a AAV to vent a fixture?

AAVs....are great

You will hear a howl of protests here in a while...

their are some here that would rather use a chain saw
and literally cut the house down to get a vent out
the roof .......instead of a 5 dolllar AAv...


I like them and use them sometimes..and they can be life
savers in difficult situations..

In my old home I installed them extensively in the basement remodel where I could not get a vent
out of the house without doing the chain saw method...

their is one behind the lavatory,...one behind the
laundry, and one behind the toilet....

they are all still working to this day...15 years later...


depending on the codes......

we all have our own crosses to bear...

to each his own.....



http://tbn0.google.com/images?q=tbn...s.lowes.com/general/p/poulan_gas_chainsaw.jpg

Mark pretty much summed it up. First make sure they're legal in your area. If they are avoid using them if possible but if you don't have much of a choice go ahead and use one.

However you install them, make sure you leave access to the valve on the chance you need to replace one of them.

Aav

AAV's have three advantages.
1. They are cheap
2. They are easy to install.
3. The save installation costs

Their main disadvantages are;
1. If the underground drain line stops up anywhere the sink will not drain and you will not know if it is just the sink drain or the entire plumbing system that needs servicing.
2. The will reduce negative pressures but not positive pressure which can also cause a sink not to drain.
3. They are a handyman way to do plumbing unless the situation is so serious that they are the only solution. Ancient plumbing systems being about the only ones which qualify.

Aav

AAV's have three advantages.
1. They are cheap
2. They are easy to install.
3. The save installation costs

Their main disadvantages are;
1. If the underground drain line stops up anywhere the sink will not drain and you will not know if it is just the sink drain or the entire plumbing system that needs servicing.
2. The will reduce negative pressures but not positive pressure which can also cause a sink not to drain.
3. They are a handyman way to do plumbing unless the situation is so serious that they are the only solution. Ancient plumbing systems being about the only ones which qualify.