# AAV installation **URL:** \ **Category:** Plumbing Inspections\ **Created:** [May 29, 2008, 9:37pm UTC](https://forum.nachi.org/t/aav-installation/28702 "2008-05-29T21:37:54Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![lprinzi](https://avatars.discourse-cdn.com/v4/letter/l/3da27b/32.png) [@lprinzi](https://forum.nachi.org/u/lprinzi)\ **Post date:** [May 29, 2008, 9:37pm UTC](https://forum.nachi.org/t/aav-installation/28702/1 "2008-05-29T21:37:54Z")
I ran across this today and never saw it before. It appears to be an Air Admittance Valve(??) installed on the end of a vent stack. Anyone have info on if this is a proper installation? Thanks ![0008.JPG](https://global.discourse-cdn.com/internachi/original/3X/b/7/b7d1c76f46721a834ab5a8d5277a5f7ca117e7bb.jpeg) ---
**Author:** ![ldapkus](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/ldapkus/32/58272_2.png) [@ldapkus](https://forum.nachi.org/u/ldapkus)\ **Post date:** [May 29, 2008, 11:38pm UTC](https://forum.nachi.org/t/aav-installation/28702/2 "2008-05-29T23:38:25Z")
[www.\*\*airadmittancevalve.com](http://www.airadmittancevalve.com) \*\* ---
**Author:** ![lprinzi](https://avatars.discourse-cdn.com/v4/letter/l/3da27b/32.png) [@lprinzi](https://forum.nachi.org/u/lprinzi)\ **Post date:** [May 29, 2008, 11:52pm UTC](https://forum.nachi.org/t/aav-installation/28702/3 "2008-05-29T23:52:14Z")
What is that link supposed to tell me? ---
**Author:** ![jpope](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jpope/32/59425_2.png) [@jpope](https://forum.nachi.org/u/jpope)\ **Post date:** [May 30, 2008, 2:00am UTC](https://forum.nachi.org/t/aav-installation/28702/4 "2008-05-30T02:00:11Z")
I doubt it’s actually an AAV. It looks like a cap of sorts, but I’m not sure why it’s there. Installing an AAV in such a manner would completely defeat the purpose for having an AAV to begin with. . . ---
**Author:** ![Mark\_Thorman](https://avatars.discourse-cdn.com/v4/letter/m/e36b37/32.png) [@Mark\_Thorman](https://forum.nachi.org/u/Mark_Thorman)\ **Post date:** [May 30, 2008, 2:23am UTC](https://forum.nachi.org/t/aav-installation/28702/5 "2008-05-30T02:23:20Z")
I have recently started seeing these here on maui. They are always on homes with a septic tank and typically high wind areas although no has a good explaination for them. I though maybe to prevent back pressure on traps? Mark Thorman Thorman Home Inspections [www.mauihomeinspections.com](http://www.mauihomeinspections.com) ---
**Author:** ![jgilleland](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/jgilleland/32/1326_2.png) [@jgilleland](https://forum.nachi.org/u/jgilleland)\ **Post date:** [May 30, 2008, 3:48am UTC](https://forum.nachi.org/t/aav-installation/28702/6 "2008-05-30T03:48:58Z")
Never seen one used that way. If there are high winds in the area the some plumbers put a hook - upside down trap to keep the wind from blowing the traps in the house. ---
**Author:** ![Mark\_Thorman](https://avatars.discourse-cdn.com/v4/letter/m/e36b37/32.png) [@Mark\_Thorman](https://forum.nachi.org/u/Mark_Thorman)\ **Post date:** [May 30, 2008, 4:03am UTC](https://forum.nachi.org/t/aav-installation/28702/7 "2008-05-30T04:03:15Z")
I thought it was a Maui thing. Things get done a little differently here. Mark Thorman Thorman Home Inspections [www.mauihomeinspections.com](http://www.mauihomeinspections.com/) ---
**Author:** ![lprinzi](https://avatars.discourse-cdn.com/v4/letter/l/3da27b/32.png) [@lprinzi](https://forum.nachi.org/u/lprinzi)\ **Post date:** [May 30, 2008, 5:25pm UTC](https://forum.nachi.org/t/aav-installation/28702/8 "2008-05-30T17:25:36Z")
Thanks for the responses. It kinda stumped me too. The installation is on a home without a septic but it is in St. Augustine, Fl. Maybe the high wind theory is the reason, but it’s only installed on one vent.