Hello,
Can I use an Automatic Vent device to vent a washer machine drain, or use a loop vent? Thanks. Nara

Hi Nara...

As plumbers we always prefer to see an individual vent run for all fixtures and then connected into the vent system. Simple fact is that anything mechanical can fail so always best to install non-mechanical when possible. If unable to run an individual vent or too costly and if automatic vents are allowed in your area then an AAV is the other way to go... see image. It should be piped in so that it is a minimum of 6-12" above the PTRAP.

AAVs must remain accessible because as I mentioned they can fail allowing sewr gas to escape into the home. In this case, you would simply replace the AAV so not a big deal as long as accessible.

Let us know if you need more info...

MARK

Hello Mark,
Thank you very much for your answer, that helps me a lot. I read books and search in the Internet, but your answers are the fastest way and very accurate. Thank you. :)

Here's Marks drawings as they would look installed. (see images) Regards, Tom