Re: Vents are important; have it checked
Posted by ED on April 02, 2004 at 15:25:16:
In response to Re: Vents are important; have it checked
It is conceivable that all the fixtures could be tied into one vent stack passing through the roof.
If you look up into your attic you will see a maze of vent pipes as you said you have three baths on the second floor, assuming you do not have a floor covering the ceiling joists up there.

Auto-vents, are but yet another name for Air Admittance Valves. They are also called Studor Vents, Cheater Vents, Air Admittance Vents, Shur-Vents, Genova-vents etc.

These are sometimes substituted for traditional vent-to-roof installations. They are not meant to replace them. Code dictates at least ONE traditonal vent-to-roof in all installations in a home. These can open up in attics. Traditional vents are not permitted to open in an attic!

These AAVs open under negative pressure like when a toilet is flushed to let (admit) air into the system to facilitate proper draining. They "auto"matically close afterwards to prevent sewer gases from leaking out. That's why they can be installed in an attic and traditional vents can not open because they would allow sewer gas to escape.

Normally AAVs are used when vent-to-roof or tie-ins to those vent stacks can not be accomplished.
Plumbers traditionally favor regular venting principles as there is little liklihood of failure of a regular vent. AAVs can fail after a passage of time. They also need an open access point, should problems develop with them.

: Thanks for the replies Deb, Ed and Jimbo -- this house is about 16 years old and I've lived in it for the past 4+ years. The new roof went on last year. SO there is one vent through the roof that I thought was for the interior shower-- but it could be for the toilets.... it's just strange because there'd have to be alot of creative routing to get all the vents to come together through one outlet (the toilets are in all different relative locations).

: What would I look for for to determine if there are "auto vents"? -- also would I just contact a general plumbmer to take a look or some other building specialty? thanks again

: :As alluded to by Deb and Ed, it is almost inconceivable that 5 toilets could flush properly if not vented. So the question then is are they vented correctly. If the vents were left open to the attic, this lets the fixtures vent but puts sewer gas in your attic. This is not a good thing. If it is a new house, contact your builder for an explanation. Otherwise find a well qualified professional to check it out. Everything may be fine, but this is important enough that you need to know the answer.

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