RE: Black/Gray venting.....Need some advice!!!

[mrt_1111]

If connecting the pipes. What happen if the black tank over flowed and flowed in the vent pipe? The gray tank will fill up and into the shower? I read about people over filling their black tank (never seen it) and it dump on the roof.

[BFlinn181]

Originally Posted by mrt_1111

If connecting the pipes. What happen if the black tank over flowed and flowed in the vent pipe? The gray tank will fill up and into the shower?

For the black tank to overflow, you'd have to ignore the fact that the toilet is no longer draining. As long as fortisi876 is putting the Y connector to join the vents above the level of the toilet valve, I can't imagine it would be an issue, especially as the natural place to join the vents would be in the upper part of the pictured closet with exposed vents showing.

I'm at a loss to see why so many concerns are being voiced. You only drain one tank at a time, so the venting action won't be harmed. The only way a black tank could overflow would be to turn on a tank sprayer and walk away. I think fortisi876 has better sense than that.

As JFXG said, multiple drains are hooked up to one roof vent in homes all the time. (at first when I read JFXG's post, I thought, "Who has grey and black tanks in their home?" Then I realized he was talking multiple drains hooked to one vent.)

[mrt_1111]

I think it`s a good idea, but post 139.

http://www.irv2.com/forums/f258/stup...174901-10.html


Post 6
http://www.irv2.com/forums/f115/darwin-award-86839.html

[britcon]

Why not just extend one of the pipes a few inches with a coupler so flanges clear each other. Your other roof protrusions ( AC Units ), are higher all ready so you are not loosing clearance.

[johnboy99]

Add a 90 degree elbow to one or both that will move them apart, no roof issues, and cheep fix...

[mel s]

Originally Posted by exrench

What point is there to alter the OEM set-up? The vent is to the outside and the wind carries the odor away. What more is to be accomplished?

exrench
I agree
Putting different vent caps on the "stink pipes" is like putting Band-Aids on a broken leg.....(they may cover-up the real problem but they DON'T FIX anything).
If/when everything in the sewer drain systems is working as designed NO odor will/can enter the coach....(either that OR the occupants are doing something wrong)!

Simply stated: If odor is getting into a coach there something is WRONG that needs FIXING!

Mel
'96 Safari

[GoldWing2003]

Why not tie together on the roof? That way you no not need to patch roof.

[Rkc02]

I agree with Goldwing2003: tying together above the roof could be done with only an additional 3 inches or so - should not be a height issue and solves the problem without a roof patch.

[fortisi876]

Appreciate all the replies and sharing the concerns, truth be told I went with my decision before most the the replies on this page.

Overflowing the black tank was never even a thought, I seriously doubt I'd ever let that happen so I'm not too concerned. Besides, after opening the OEM vent caps up, there is NO WAY water overflowing out of those vent pipes would have been a good thing since they weren't sealed off to properly keep water from flowing inside through the roof. So either Monaco did a very poor job in execution OR they never thought the system would get backfilled to that point without something else giving way. I'm including more photo's to show what I'm talking about and the completed project.

As you can see, the abs pipe terminates BEFORE the rubber boot, if water came spilling out of that vent no doubt it would have all flowed right back into the roof/ceiling.

[BFlinn181]

Looks like a nice job, but wait for the critics of mixing ABS and PVC plastic pipe! They're out there. Tell them you used Oatey 4 oz. ABS to PVC Transition Cement-309003 at The Home Depot

It's only a vent, at most you have stinky air going in/out the pipe.

[fortisi876]

LOL...that's exactly what I used, hence the green residue in the joint.

[gemini5362]

Originally Posted by mel s

exrench
I agree
Putting different vent caps on the "stink pipes" is like putting Band-Aids on a broken leg.....(they may cover-up the real problem but they DON'T FIX anything).
If/when everything in the sewer drain systems is working as designed NO odor will/can enter the coach....(either that OR the occupants are doing something wrong)!

Simply stated: If odor is getting into a coach there something is WRONG that needs FIXING!

Mel
'96 Safari

Ok I will ask the question. I drain my black tank on a regular basis. I use the flush jet and flush out the tank when I empty it. I fill the tank back 6 per cent full of water. In the past I have filled the tank 75 per cent full of water with a cup of pine sol in the tank. I then drove for 200 miles on curvy mountain road. I regularly put pine sol or sometimes simple green in the tank and fill it 75 per cent full and let it set for 2 days when I am leaving the coach for a weekend. My vent is not clogged up. I still occasionally get smells from my black tank. What do you suggest I fix.

[BFlinn181]

You have to understand, Mel S s**t don't stink.

For the rest of us, any negative air pressure in the RV can cause black tank odor to enter when the toilet is flushed, especially toilets that don't have a trap, just a rotating valve that opens directly into the black tank. A vent cap, as fortisi876 installed, or the Cyclone type makes sure there is negative pressure up the vent no matter which way the wind is blowing. Traveling with the roof vent 'cracked' or a window open will certainly draw gases up the toilet if flushed, and with a window or roof vent open when stopped it's still possible to have negative pressure in the RV that over powers the venting action of a standard vent cap causing odors into the RV.

This video shows a demonstration clear black tank comparing various sprayers. When I saw it, I was struck by how much 'stuff' is left in the tank, even after the best sprayer and rinse cycles.

https://www.youtube.com/watch?v=dfTd0Slt_cU

[mrt_1111]

I find the siphon vent cap works quite well. Job well done