There is a verticle pipe next to the laundry "rinse pipe" (or standpipe I think it's also called) with a black cap on it. Last night my husband wiped off a thick layer of dust to reveal that the cap says "Air Vent". Is doesn't seem to me like too much air is venting if there was a thick layer of dust on it. Also, is it common to have an air vent not venting "out" somewhere... just into the air of the house? I'm sure I'm just not understanding the mechanics of it.

The helpful people who posted to my original question (posted yesterday, same title) said all the gurgling in the kitchen sink and back up of water out the rinse pipe suggested a vent problem, or a clog.

Do these air vent caps need to be adjusted or replaced? My guess is that the cap is probably a good 15 or 20 years old. I have doubts that the cap is doing it's job based on the gurgling sounds in my kitchen sinks when the laundry rinses, and the water back up we experience if the kitchen sink is plugged.

Thank you so much for all the help... it really has been fun trying to get to the bottom of this and learning a little something about a subject I know nothing about in the process!

The air vent is the pipe that allows air to help with the water going down the drain. If you plugged up this air vent nothing would run down the drain. You sound like you have a clog in the line. Don't mess around with the air vent... as that is not your problem. There is a clog somewhere down the drain.

twinkiedooter, we added Cess-flo to our standpipe and the water isn't backing out the top of the pipe anymore, so the Cess-Flo (suggested by our plumber after he did nothing and handed us a $75 bill) cleared something away. I'm sure it didn't totally get rid of the clog, so hubby is going to snake the line today.

While addressing the back up of water, several members suggested a vent problem because of the gurgling sound in the kitchen sink when we do laundry. If I can kill 2 birds with 1 stone and get rid of the gurgling sound at the same time, that would be fantastic!

In your opinion, do air vents go bad or stop working correctly? I'm kind of concerned that a thick layer of dust might suggest that the air vent is no longer working properly. Of course, I don't fully understand the "mechanics" of an air vent cap... I'm kind of assuming that it vents, somehow, out the top of the cap.

What do you think?

I appreciate the time you took to answer! Thank you!

Gurgling is caused by air not making it into the vent. While the best way is to run the vent to the roof, sometimes it is expedient to use an air admittance valve. It lets air in while not letting flammable, toxic, bad smelling sewer gas out. A thick layer of dust on the top wouldn't stop air from going in the lower edge. They can stick and fail. So check it out and see what others here have to say. It is a touchy subject, but many of the answers here aren't the best.

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Originally Posted by labman

Gurgling is caused by air not making it into the vent. While the best way is to run the vent to the roof, sometimes it is expedient to use an air admittance valve. It lets air in while not letting flammable, toxic, bad smelling sewer gas out. A thick layer of dust on the top wouldn't stop air from going in the lower edge. They can stick and fail. So check it out and see what others here have to say. It is a touchy subject, but many of the answers here aren't the best.

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Thanks, Labman... it couldn't hurt to replace the cap. Tom had posted a picture of an AAV in another post, and my cap looks nothing like what he posted, so we're going to replace what we have with what Tom posted the picture of. I apprecaite your help! I feel comfortable with your suggestions because you are quick to defer to the experts on the board! That says a lot! :)