Air Admitance Valve

Is it acceptable to install an AAV in any position other than vertical? Unable to determine brand so I cannot search installation instructions by manufacturer. Any help would be appreciated.

Most of the time it should be on the horizontal line mounted on a vertical stem.

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The UPC forbids their use all together, I believe. Check to see which plumbing code the applicable jurisdiction has adopted.

You are correct Jim, and forgot to say that. They are illegal to use in Maine unless for a renovation of existing conditions and approved by the AHJ.
Thanks for picking up on that. :slight_smile: