Bubbles in the shower

[ostbob]

2006 Lexington 283 GTS
When we drain the kitchen or bathroom sinks sometimes bubbles and gurgling sounds come up from the shower drain.

The shower drain drains slow where as the others drain very fast. We have used Draino and plungers but still have the problem.

Forest River sent me a Waste water diagram which shows the blk and gry systems are not even connected and both have separate vent pipes to the roof. However, their drawing is dated 2010 so obviously its not correct cause I only have one vent pipe for the black tank and none for the grey tank.

I ran a high pressure water hose down the black tank roof vent pipe and as I suspected sewer waste came up into the shower drain.

Anyone have any other ideas or know how this systems are really connected?
I looked from underneath the RV and can't really see much of the piping into the blk or gry tanks so I assume there in the floor.

[wildcatter]

I have three tanks (2 grey 1 blk), all three tanks are vented thru one pipe thru the roof, your home is no different, all the plumbing is connected to one vent. All your tanks need to be vented or they will not drain correctly. It sounds like you have a blocked vent somewhere. Also, your grey water may look like blk water if it sits in the tank long enough.

[bob213]

Sometimes when not vented to the roof there is a vent under the bathroom sink. It could be clogged or need replacing.

It would look something like this:
https://www.lowes.com/pd/Oatey-1-1-2...ent/1000363773

[FL-mph21]

when my Toilet is nearing full, it sort of bubbles

good reminder for me

marc

[ostbob]

Tanks were only about 1/3 full and it doesn't seem to matter how full they are. However it does drain better when fully level vs being 2-3" lower in the front.

No vent under the sinks.

[nomad297]

Originally Posted by bob213

Sometimes when not vented to the roof there is a vent under the bathroom sink. It could be clogged or need replacing.

It would look something like this:
https://www.lowes.com/pd/Oatey-1-1-2...ent/1000363773

Both tanks are atmospherically vented. An air admittance valve will not work if there is not an atmospheric vent connected to a drainage system. The OP’s black and gray tank vents are tied in together, and from the explanation given, the gray tank vent is going straight through the roof from the tank and the black tank vent is tied into it on the vertical somewhere inside of a wall. This is why water came up into the shower when the hose was put into the vent on the roof. It was coming from the gray tank and not the black tank. The shower is bubbling because the air admittance valve on the gray water system is not opening. It needs to be replaced.

Bruce

[nomad297]

Originally Posted by ostbob

No vent under the sinks.

Then you need to install one on one of your gray system drains.

Bruce

[nomad297]

If you want to test the theory of whether or not you need an air admittance valve, remove the trap from one of your sinks and drain water into the other sink. Removing the trap will allow air into the system, just like an air admittance valve would.

Bruce

[CedarCreekWoody]

Are you sure no AAV vents? They can be difficult to spot. Higher than the trap under the sink. If you find one just unscrew and remove it. Replace with a new one if that fixes the problem.

[ostbob]

OK, you guys were right I went and double checked and found one under the kitchen sink and those lines connect to the bathroom sink directly behind the wall. It's too late and difficult to get to so now my question is this.

These two sinks are draining perfectly, super fast etc. can this AAV still be causing my shower drain to bubble and how would this explain the Blk tank vent forcing water and gases up the shower drain when I ran water down the blk tank vent pipe from the roof?

I would assume this AAV is working perfectly because of the way the two sinks drain so fast.

There are no access panels to remove so I can't see if the blk tank vent pipe connects with the grey water drain lines from the kit/Bath sinks.

I've also attached the diagram for a 2010 which is the only one Forest River has been able to provide. Even if blk tank vent pipe #37 connected where it meets grey water Kit/Bath line #32 there is no way to access it.

[ostbob]

Originally Posted by nomad297

Both tanks are atmospherically vented. An air admittance valve will not work if there is not an atmospheric vent connected to a drainage system. The OP’s black and gray tank vents are tied in together, and from the explanation given, the gray tank vent is going straight through the roof from the tank and the black tank vent is tied into it on the vertical somewhere inside of a wall. This is why water came up into the shower when the hose was put into the vent on the roof. It was coming from the gray tank and not the black tank. The shower is bubbling because the air admittance valve on the gray water system is not opening. It needs to be replaced.

Bruce

Bruce
Its the blk tank that has the roof vent and I found the AAV valve under the kitchen sink which is also connected to the bathroom sink. BOTH of them drain great all the time.
IF this AAV was defective in some way would both of these sinks still drain great like they do?

Would having this valve eliminate the need for a grey tank roof vent?

Would this explain the waste water smell that came up in the shower drain?

Wife says can't be sure it was actually waste water and not bad grey water causing the smell but it happened when I was running water down the blk tank roof vent.

Thanks for your input and help.

[nomad297]

Originally Posted by ostbob

Bruce
Its the blk tank that has the roof vent and I found the AAV valve under the kitchen sink which is also connected to the bathroom sink. BOTH of them drain great all the time.
IF this AAV was defective in some way would both of these sinks still drain great like they do?

Would having this valve eliminate the need for a grey tank roof vent?

Would this explain the waste water smell that came up in the shower drain?

Wife says can't be sure it was actually waste water and not bad grey water causing the smell but it happened when I was running water down the blk tank roof vent.

Thanks for your input and help.

Before I answer this, I would like to know if the gurgling happens both when you have the gray tank drain valve open and when you have it closed. Also, if it happens when the valve is closed, does the gurgling get more pronounced the fuller the gray tank gets?

Bruce

[CedarCreekWoody]

It is sure sounding like a plugged vent stack.

[nomad297]

Originally Posted by CedarCreekWoody

It is sure sounding like a plugged vent stack.

In all of my (almost) four decades of being a plumber I have never run across a plugged vent stack, except for a couple where a non-plumber purposely capped one because he didn’t know what he was doing when he was remodeling or “fixing” something. I have run across plugged vents, but only in the case of a wet vent, where all of a bath group’s fixtures are vented through the lavatory drain and vent. In this case, it is only the drain portion of the lavatory that has become clogged over time, restricting air flow through the lavatory drain to the rest of the bath group’s fixtures. I snake the sink drain and everything is good. When customers have a problem like the OP is describing, they almost always suggest to me that they have a clogged vent because they read about it on the internet. Sure, a clogged, capped or plugged vent can cause drainage problems, but it almost always is not the case.

Bruce

[nomad297]

If the OP wants to work out whether or not his tank is atmospherically vented, he needs to either remove a trap from one of his sinks (as I suggested before) or remove the now-discovered air admittance valve and close the gray tank drain valve. He then needs to take a plastic grocery bag and place it over whichever pipe he has opened up and give it about a fist-sized amount of “balloon” slack and rubber band it to the pipe. He then needs to go to the other sink, fill it up, then have somebody drain it as he watches the plastic bag. The plastic bag will either get sucked into the open pipe or it will blow up like a balloon. If it gets sucked in, there is an atmospheric vent and he needs to replace the air admittance valve. If the bag blows up like a balloon, there is no atmospheric vent, or there is an obstruction in or to the vent. A new air admittance valve will not help in this situation — he will have to work out a way to atmospherically vent the tank. It is also possible that the vent for the gray tank is pushed too far into the tank, so he might want to try this experiment with the tank empty, then again with the tank almost full.

Keep in mind that air admittance valves aren’t a substitution for an atmospheric vent. There must be an atmospheric vent in any plumbing system for an air admittance valve to work.

Bruce

[HerveVR]

Don't get foolled by your nose.

The odours of the grey tank and the black tank are nearly at the same level on the «perfume» scale.

[ostbob]

Originally Posted by HerveVR

Don't get foolled by your nose.

The odours of the grey tank and the black tank are nearly at the same level on the «perfume» scale.

Even if the're the same can't figure out how running water down the blk tank would force bubbles and odors up the shower drain.

Taking to dealer for some paint work today and we'll see what they can find on this issue too.

[Indymule]

Originally Posted by nomad297

Both tanks are atmospherically vented. An air admittance valve will not work if there is not an atmospheric vent connected to a drainage system. The OP’s black and gray tank vents are tied in together, and from the explanation given, the gray tank vent is going straight through the roof from the tank and the black tank vent is tied into it on the vertical somewhere inside of a wall. This is why water came up into the shower when the hose was put into the vent on the roof. It was coming from the gray tank and not the black tank. The shower is bubbling because the air admittance valve on the gray water system is not opening. It needs to be replaced.

Bruce

You need to reread nomad's post. He is explaining why running water down the vent pipe is causing water to bubble in the shower. They black and grey tank share the same atmospheric vent.
You never said anything about black water backing up into the shower under normal use, only that it bubbled in the shower when the sinks were draining. I think you are confusing yourself with putting water down the atmospheric vent.

[nomad297]

Originally Posted by Indymule

You need to reread nomad's post. He is explaining why running water down the vent pipe is causing water to bubble in the shower. They black and grey tank share the same atmospheric vent.
You never said anything about black water backing up into the shower under normal use, only that it bubbled in the shower when the sinks were draining. I think you are confusing yourself with putting water down the atmospheric vent.

I suppose I should just draw a riser diagram, take a picture of it and post it here. I can’t think of a more simple way to put it into words than I already have.

My son went through school with ADHD and sometimes the only way to help him understand things was to draw pictures. I think that even some people without ADHD can’t comprehend simple written instructions without pictures.

Bruce

[WFD]

Originally Posted by nomad297

I suppose I should just draw a riser diagram, take a picture of it and post it here. I can’t think of a more simple way to put it into words than I already have.

My son went through school with ADHD and sometimes the only way to help him understand things was to draw pictures. I think that even some people without ADHD can’t comprehend simple written instructions without pictures.

Bruce

That explains why I do so well with Ikea and Lego assembly instructions...just pictures and no words!!