Why would my AAV valve under my bathroom sink continually fail?... I bought a place in March that had a 'periodic' odor problem. Having had the same issue with my motorhome I looked for and found and AAV valve under both the kitchen and bathroom sinks. That was 6 months ago. The previous owners had only been 'in and out' periodically and some of the smell was coming from the drains - so I also replaced all of the 'p' traps ... Everything was fine for about 4 months and then the valve under the bathroom sink failed. I replaced it and it was fine for about a month. 3 days ago it failed again and I replaced it. Today it failed again. I am replacing these with new parts, not 'cleaaned' or refurbished. WHY would the one location start continuously failing. All my drains work fine. They are not slow, sluggish or otherwise compromised.
Any suggestions would be appreciated. I am at a loss... and this could become really expensive!

call the manufacturer of the valve. they should care that their products are failing ???

Do you have at least 1 vent penetrating the roof to atmosphere

No it is not.... this is an older Park Model trailer that is plumbed in to the septic system in the park. The valve under the kitchen sink has not failed since I replaced it originally. This morning I replaced the one under the bathroom sink.... after replacing it yesterday and a month ago. This afternoon I still have some odor from the undersink in the bathroom.... I'm not understanding why

Maybe a toilet needs a new seal between toilet and flange
Does the toilet leak or wobble

did you put pipe dope on the male threads of the AAV ?

Is it mounted high enough that waste water is not fouling the internals?

No it does not

Instructions on the valve say not to

Yes - it is - 4" is required and this one is 5"

>This afternoon I still have some odor from the undersink in the bathroom.... I'm not understanding why

It sounds like you interpret "some odor" as "AAV valve failed." In a previous reply, BSipps mentioned that the odor may be coming from the toilet.

Personally I find it extremely difficult to localize odors, so the only way I can solve such problems is to cap the AAV pipe with one of these:
[www.plumbingsupply.com]

Then wait to see if the odor returns. If it does, the source is elsewhere. If the odor does not return, the AAV valve indeed failed.

I would do some tests to narrow things down.

Does the odor seem to be present all the time? Days only nights only or when you flush a toilet or after taking a shower etc...?

Other culprits of odor - ila floor drain whose trap has dried up; a toilet wax ring broken seal; a sink's overflow hole that has some nasty build up; or even a dead rodent behind walls.

I would put a plastic bag over the AAV and leave some air in and tape it closed. If you fill up your sink then pull the drain stop the water will fill the pipe and drain. That plastic bag should not expand from positive pressure. If you run other fixtures like a toiler, it should collapse that plastic bag because it's pulling air into the AAV.

You can also try taping shut the sink drain and overflow holes to see if that stops the odor.

DITTO

Quote

I would put a plastic bag over the AAV and leave some air in and tape it closed. If you fill up your sink then pull the drain stop the water will fill the pipe and drain. That plastic bag should not expand from positive pressure. If you run other fixtures like a toiler, it should collapse that plastic bag because it's pulling air into the AAV.

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