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buddywiser · Jan 30, 2007, 11:10 AM

Hi, newbie here! I'm a total amateur when it comes to plumbing, so I thought somebody here could help me out. When we use the upstairs shower, a horrible sewer smell comes out from under the kitchen sink. The shower is located in the room directly over the kitchen. Nothing out of the ordinary as far as the shower is concerned. We do have a problem where some of the traps throughout the house dry up and we have to run some water in them. It's a pretty big house and some of the sink don't get used for weeks, so I'm not too worried about that. Here are a couple pictures below the kitchen sink:

Picasa Web Albums - Hamiltons - Kitchen

As you can see, there are holes cut out in the back of the sink for the pipes. I thought the smell may be coming in from the hole from another part of the house, but I sealed the holes with plastic , took a shower, and the smell was just as bad.

More info: There is a dishwasher and a disposal installed. Both of these are brand new, so I think I can rule them out. The smell does NOT come up from the kitchen sink drain. Not sure if you can tell or not, but the water drains through the floor and not through the back. So I'm hoping that I've narrowed it down to that piece on the left (2nd pic) that is capped off. I'm not sure what the function of that is. It has a NOVAVENT cap on it. Is it possible that the leak is in this piece. Does the NOVAVENT cap let air in. Could it possibly be letting air out?

Also, I found some vents terminated in the attic. Not sure where the main vent out is.

Anybody have any more suggestions?

buddywiser · Jan 30, 2007, 05:10 PM

Originally Posted by buddywiser

Hi, newbie here! I'm a total amateur when it comes to plumbing, so I thought somebody here could help me out. When we use the upstairs shower, a horrible sewer smell comes out from under the kitchen sink. The shower is located in the room directly over the kitchen. Nothing out of the ordinary as far as the shower is concerned. We do have a problem where some of the traps throughout the house dry up and we have to run some water in them. It's a pretty big house and some of the sink don't get used for weeks, so I'm not too worried about that. Here are a couple pictures below the kitchen sink:

Picasa Web Albums - Hamiltons - Kitchen

As you can see, there are holes cut out in the back of the sink for the pipes. I thought the smell may be coming in from the hole from another part of the house, but I sealed the holes with plastic , took a shower, and the smell was just as bad.

More info: There is a dishwasher and a disposal installed. Both of these are brand new, so I think I can rule them out. The smell does NOT come up from the kitchen sink drain. Not sure if you can tell or not, but the water drains through the floor and not through the back. So I'm hoping that I've narrowed it down to that piece on the left (2nd pic) that is capped off. I'm not sure what the function of that is. It has a NOVAVENT cap on it. Is it possible that the leak is in this piece. Does the NOVAVENT cap let air in. Could it possibly be letting air out?

Also, I found some vents terminated in the attic. Not sure where the main vent out is.

Anybody have any more suggestions?

Update: We never use the tub near the shower, but I thought I'd run some water it and see if I got the smell from that too. And yes, it's the same thing. Yuck. Anybody?

iamgrowler · Jan 30, 2007, 06:25 PM

I'm guessing that the air-admittance valve (the NOVAVENT) has failed.

Frankly, I'm having a hard time understanding why the person who did this work positioned the AAV where they did.

They could have eliminated the 90 going into the top of the tee altogether if they had:

A) Raised the tee a few inches above the bottom of the cabinet.

B) Used an appropriate sanitary tee, instead of a vent tee.

C) Drained the p-trap into the side inlet of a sanitary tee, rather than the top of the vent tee.

D) And put the AAV into the top of a sanitary tee, rather than into the side inlet of a vent tee.

Here is a photo of roughly how it should look -- You can't see it, but the AAV is coming out the top of the sanitary tee.

buddywiser · Jan 30, 2007, 06:49 PM

Thanks for the reply :) I'm still a little confused about the Novavent. Is this an AAV? All Google brings up is Anti-Syphon. Are they the same thing or serve the same purpose?

iamgrowler · Jan 30, 2007, 06:59 PM

Originally Posted by buddywiser

Thanks for the reply :) I'm still a little confused about the Novavent. Is this an AAV? All Google brings up is Anti-Syphon. Are they the same thing or serve the same purpose?

The Novavent is a brand of AAV, but to the best of my knowledge, it has never received IAPMO approval, as several other brands have.

buddywiser · Jan 30, 2007, 07:16 PM

So it's possible that if I just get one of these, it could solve my problem?

Amazon.com: Auto Vent Valve, 1 1/2": Tools & Hardware

iamgrowler · Jan 30, 2007, 07:25 PM

Originally Posted by buddywiser

So it's possible that if I just get one of these, it could solve my problem?

Amazon.com: Auto Vent Valve, 1 1/2": Tools & Hardware

I wouldn't recommend buying the same brand, especially when it lacks approval from the foremost testing laboratory in the industry.

OTOH, I *would* recommend the Studor AAV.

Just my two pence.