# Vent Under Sink!!!!????



## rwc454 (Aug 18, 2005)

I've read on here before of a couple of people having odor problems from the little grey water tank vent located under the sink. Man this happened to us for the first time this weekend. Ive been racking my brain trying to figure out what would be causing this. We have only used the sink to to wash a few dishes in the past. NOTHING (food etc...) goes down the drains. I tried using the grey tank lemon fresh cleaner from walmart to no avail. Iv'e flushed and reflushed the grey tank and still get that nasty sulfer, rotten egg smell. I'm thinking about sealing this vent off. Is there a vent for the grey tank on the roof or just a black tank vent? Sorry so long but we definately cant go camping until this is takin care of. I'm standing by for instructions and all of your inputs on this. Thanks alot. Glad i found this site.


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## CamperAndy (Aug 26, 2004)

Since I do not own a 21rs my answer may not help but check your roof. If you see 2 vent caps then you should be able to cap the vent under the sink. Most likely this is a vacuum break for the sink and if you cap it then the sink will not drain smoothly but will bubble slowly.


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## Thor (Apr 7, 2004)

Welcome to Outbackers.com action

I suggest that you do not block off any vents. Also there should not be any smell coming from your grey tank. All drains should have a 'P' trap that hold water in them to prevent order from coming up thru the drain.

Suggestions:

1 - Check to ensure all fittings are tight and proper.
2 - Fill your grey tank full and add a cup of bleech and let sit for awhile
3 - Dump the grey tank and fill with fresh and dump again.
4 - Ensure your 'P' traps are full of clean water
5 - While dumping your grey, check to see if it is the same smell - maybe it is not your grey tank at all????

Good luck and let us know how it goes.

So far I have had no issues with grey water at all.

Thor


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## hurricaneplumber (Apr 12, 2004)

The sink vent is called a air admittance valve and is required to keep the trap full preventing siphoning.

Each fixture has a trap vent point and the tank is also vented to the roof.

The valve could be defective.

If you dump lemon scented stuff into the gray tank, does it smell like lemons under the sink after this???? It should if the valve is the problem, if no lemon smell there may be a leak that is festering bacteria causing the foul smell.

Hand tighten all of the drain fittings, plastic drain piping loosens up with the expansion and contraction of hot-cold fluids dumped down the drain.

A air admittance valve can be obtained at Lowe's for around 3-4$.









Air Admittance Valves by StudorÂ®: 
pressure sensitive valve 
opens upon fixture discharge 
admits air into drain, waste and vent systems 
closes to prevent foul air inside 
should not be exposed to outdoor elements 
considered "the standard" by some 
two different sizes to choose from 
no roof penetrations 
NSF Standard 14

Good luck

Kevin


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## Dark Green Dmax (Aug 2, 2005)

When this happened to me....i think i had the tank too full(i must had not emptied all the way from the time before. (gauge showed full) I'm assuming that because of the levels being so high, the grey water backed up into the the vertical vent...thus blocking it. so this vent under the sink was the only place available to vent fumes. I first drained the tank , then flushed it real good. I then disinfected this tank & now watchthe tank levels better & haven't had a problem since.


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## Morrowmd (Feb 22, 2005)

You mentioned "rotten egg smell". Just to cover all bases you may want to check propane fittings around the stove and oven. LP gives off a nasty odor so you know when it is leaking.

Good Luck!


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## CamperAndy (Aug 26, 2004)

Kevin - I knew we had a plumber around here some where. Are the siphon breaks or air admittance valves (sorry I called it a vacuum break earlier) on all of our trailers? I have not seen one on the 28rss. This is the kind of thing that could be missing completely if it is buried up behind the sink.


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## MaeJae (May 12, 2005)

Morrowmd said:


> You mentioned "rotten egg smell". Just to cover all bases you may want to check propane fittings around the stove and oven. LP gives off a nasty odor so you know when it is leaking.
> 
> Good Luck!
> [snapback]50254[/snapback]​


This was my first thought...I'd check for propane FIRST.

Camp-on sunny 
MaeJae


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## PDX_Doug (Nov 16, 2004)

I agree that capping any vent would be a mistake. It is there for a reason.

I also suspect a possible propane problem (Try typing that fast, three times!). As soon as you mentioned rotten eggs and sulfer smells, a big red propane flag jumped up to me.

Happy Trails,
Doug


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## hurricaneplumber (Apr 12, 2004)

Andy,

The valve is very hard to see since the plumbing is black as is the valve.

On my sink it comes out of the tail piece and there is a sanitary tee right where it goes to vertical (water goes down), at the top of this tee is the air admittance valve, mine is kinda up tight to the bottom of the sink.

I also have one on the bathroom sink, so I assume they all have them.
I believe the shower uses the gray tank roof vent since it is so close in proximity, not sure about the shower.

Using this is much cheaper and easier than running piping to vent all of the fixtures.

i would also check the propane


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## rwc454 (Aug 18, 2005)

Well today 4 in the morning i disconnected both propane tanks completely and purged all the lines. A buddy of mine told me to check propane yesterday. Let it set all day







came back to trailer and still that god awful smell. So i went to wally world and got some lemon fresh agent for grey tanks. filled both sinks up with water and lemon stuff drained and within a couple of hours no more nasty smell or should i say not as strong. I will go back in the morning to see if the smell is still there. I'm just baffled







why the smell is there in the first place. We never put any kind of food/grease/milk/soda etc... down the drain and weve only had it out four times since new last year!


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## MaeJae (May 12, 2005)

rwc454, 
Did you notice this smell while camping or when you got back?
If it was when you got back...was the "outback" bed slid IN ?

This is why I ask. When we first got our 27 I noticed a similar smell.
I checked my tanks(thought it was coming from the camode)
I checked my propane...

It turns out I was getting an odor from the material on the slide out bed when the camper was all closed up or mostly closed.

I opened the "back" door of the 27 and smelled it again (like sulfur) ...so...I put my nose up to the side of it and...that was the smelly smell.

Just a thought








MaeJae


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## merlotman (Dec 28, 2004)

We have an 05 23RS and had an odor from under the kitchen sink. I traced it to a malfunctioning AutoVent(air admittance valve). Picked up a replacement from the dealer and simply unscrewed the old and on with the new and no smell since. Dealer told me this is not an uncommon problem. The only smell we get in the camper now is some odor from the vinyl roof of the rear bed slide after it is pushed in after having been in the hot sun. That smell seems to stay in the camper for days when in storage. I have installed vent covers over my roof vents and now leave the vents open while in storage.


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