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Topic: Air bublling up in the tub drain when using kitchen sink (Read 628 times) previous topic - next topic

Air bublling up in the tub drain when using kitchen sink

When we use the kitchen sink for dishes and use lots of water, we are seeing air bubbling up in the tub/shower. My hunch is that the grey water vent stack is clogged. Thoughts? 
Fred H.
1996 Foretravel U320 4000 Build #4993 (Previous motorhomes 1985 Airstream 345, 1977 Argosy 20)
Sevierville, TN
ViewRVs.com

Re: Air bublling up in the tub drain when using kitchen sink

Reply #1 –
More than likely the air admittance valve hid under the sink or the one in the wall that vents the shower tub. Never saw the stack plugged but that could also cause you a problem.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Air bublling up in the tub drain when using kitchen sink

Reply #3 –
Having changed many Studor vents out over the years, I have found that there is nothing wrong with the cheaper black ones sold at HD or Lowe's.  Have never replaced one that I installed due to lack of working!  Just an FYI.  Remember, you also have one behind where the washer/dryer sits as well as behind the commode and under the sink to make 3.  Some have 4, but never encountered that.  I would also get up on the roof, if able and check to see if you don't have a pipe coming out for a vent and a bird has built a nest on it.  Not sure if they didn't install the studor valves in your year of coach or not, but should have.
Joe & Dottie Allen
Sold!  December 2023.      2000 U320; build # 5645
Our coach " Maxine"
Motorcade #  15922;  Escapee 150950; FMCA F330833; Boondockers Welcome;  Harvest Hosts;  Thousand Trails
'98 U320 from 2000-'06
USAF '62-'66

"Do not spoil what you have by desiring what you have not; remember that what you now have was once among the things you only hoped for." ―Epicurus

Re: Air bublling up in the tub drain when using kitchen sink

Reply #4 –
Quote from: juicesqueezer –
I would also get up on the roof, if able and check to see if you don't have a pipe coming out for a vent and a bird has built a nest on it.
Mine was filled full of wasp nests. Original vent was in poor condition so I installed the 360 vent with good results.
Amazon.com: Lippert Components 389381 360 Siphon Roof Vent Cap - White (Gen...
As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: Air bublling up in the tub drain when using kitchen sink

Reply #5 –
Quote from: dsd –
Mine was filled full of wasp nests. Original vent was in poor condition so I installed the 360 vent with good results.
Amazon.com: Lippert Components 389381 360 Siphon Roof Vent Cap - White (Gen...

Scott;  this was one of the cheapest add ons for our coach as well.  Works as it should!
As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.
Joe & Dottie Allen
Sold!  December 2023.      2000 U320; build # 5645
Our coach " Maxine"
Motorcade #  15922;  Escapee 150950; FMCA F330833; Boondockers Welcome;  Harvest Hosts;  Thousand Trails
'98 U320 from 2000-'06
USAF '62-'66

"Do not spoil what you have by desiring what you have not; remember that what you now have was once among the things you only hoped for." ―Epicurus

Re: Air bublling up in the tub drain when using kitchen sink

Reply #6 –
Quote from: juicesqueezer –
Having changed many Studor vents out over the years, I have found that there is nothing wrong with the cheaper black ones sold at HD or Lowe's.  Have never replaced one that I installed due to lack of working!  Just an FYI.  Remember, you also have one behind where the washer/dryer sits as well as behind the commode and under the sink to make 3.  Some have 4, but never encountered that.  I would also get up on the roof, if able and check to see if you don't have a pipe coming out for a vent and a bird has built a nest on it.  Not sure if they didn't install the studor valves in your year of coach or not, but should have.


5 AAV on my coach. Details in link above.
Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Air bublling up in the tub drain when using kitchen sink

Reply #7 –
Thanks for the replies.  I have some work to do.  :)
Fred H.
1996 Foretravel U320 4000 Build #4993 (Previous motorhomes 1985 Airstream 345, 1977 Argosy 20)
Sevierville, TN
ViewRVs.com

Re: Air bublling up in the tub drain when using kitchen sink

Reply #8 –
Quote from: AC7880 –
The more expensive Studor redi-vent AAV works better than the black ones with a rubber flap.

We went with the more expensive Studor vents (4). $100 vs $44.  I figure that one hour at most RV shops is $165 per hour. I just spent the savings on better vents.  :D  They appear to have resolved the issue. We've only used it a few time but the initial results are good.
Fred H.
1996 Foretravel U320 4000 Build #4993 (Previous motorhomes 1985 Airstream 345, 1977 Argosy 20)
Sevierville, TN
ViewRVs.com

Re: Air bublling up in the tub drain when using kitchen sink

Reply #9 –
Quote from: ViewRVs –
We went with the more expensive Studor vents (4). $100 vs $44.  I figure that one hour at most RV shops is $165 per hour. I just spent the savings on better vents.  :D  They appear to have resolved the issue. We've only used it a few time but the initial results are good.

Also try flushing out the pipes from the kitchen sink. They are shallow and over time can build up some debris in them.  Fill both sides kitchen sink to the top, then pull the drain plugs at the same time. Repeat 4 or 5 times to flush out the pipe completely. 


 If you do this when the grey tank dump valve is closed, it will likely bubble up in the shower. With grey dump valve open, less likely to bubble up in shower.
Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Air bublling up in the tub drain when using kitchen sink

Reply #10 –
Running a dedicted water hose into coach window every time when dumping will aid in flushing all drains. Also helps when cleaning toilet.

Re: Air bublling up in the tub drain when using kitchen sink

Reply #11 –
I had a smell coming from this kitchen sink that I couldn't place. I use a strainer and try to keep that clean. I put a flashlight down the sink drain and realize that there was an awful lot of junk down there. I don't know what junk it was cuz I didn't pull it up to look at it but filled it with a degreaser and used a chopstick to clean it out while flushing with hot water.
Since I boondock a lot, I try to use the least amount of water possible. Maybe not a great idea.
Smell is gone.
Having the vents in working condition for the plumbing system makes a big deal I found. Unfortunately for me when the previous owner had AM solar put in batteries where the splendid washer was, that meant that I had no access anymore to that area. What I had to do was going through the top cabinet and there was only a couple inches and I found that someone chose to just seal off the vent hole instead of replacing it. I had a lot of smell coming from that. New vent installed and problem went away. I do want to put a hose up on the roof and down my 360 vent that I installed a few years ago to make sure that the pipes are all clean. One of these days I'll do it.
'99 U320 40 WTFE
Build #5462,
1500 Watts Solar 600 amp Victron lithium
2012 Jeep Grand Cherokee Overland Hemi
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Retired