Black tank vent

eddiepotts · March 30, 2011, 11:21:43 AM

I am having trouble with the smell when I open the ticket window while driving. It takes about 2 seconds to fill the bus with the smell from the vacuum that is getting pulled from the open window. Am I vented wrong at the tank or what?

robertglines1 · March 30, 2011, 11:33:19 AM

one tank or two? if one you toilet slide valve should keep it from entering coach. If one vent for both make sure your water traps have water in them.

eddiepotts · March 30, 2011, 11:42:20 AM

just have the one tank for black and gray. I know I need to change the gasket for thr ball valve. I know the water traps are full. So what you are saying is if no water seal it will smell?

Len Silva · March 30, 2011, 11:53:19 AM

When you open the ticket window, you are putting a vacuum inside the bus and that is pulling the vapors from the tank(s).

Some possible solutions are:

1. Fix the toilet seal

2. Put a venturi fitting on the tank vent. http://rv-living-magazine.com/rv-tank-vents.html

3. Put a power vent on the tank vent http://www.lslproducts.com/MK-IVPage.html

4. Open another window in the bus to keep positive pressure in it.

eddiepotts · March 30, 2011, 12:22:27 PM

I will look into that venturi when I get home. I don't think I am vented to the roof. At least I have never seen it up there. It may be just in the bay. Would there be enough air flow if I went to the bottom of the bus with the vent line if needed?

bevans6 · March 30, 2011, 12:41:11 PM

The vent should be to the roof in a constantly rising run of pipe, so that methane gas can rise out of the tank. A vent sideways or down will trap the methane, which can be quite dangerous. The vent should definitely not just be to inside a bay!

That said, thousands will now say they vent out the bottom and their bus never blowed up. True, but...

Basically you have to seal things as well as possible, and try to figure out a way that the pressure inside the tank is lower than that inside the bus. Not opening the ticket window is the first step, it pulls everything inside the bus odour-wise forwards. I think that opening a rear window would raise the pressure inside the bus.

Brian

eddiepotts · March 30, 2011, 12:49:08 PM

I don't have the option of opening a rear window

For one I don't have one ( well I do but it swings out) and two I could not reach it if I did. I only open it if someone smokes to suck it out. I get grief on either smell. I was just hoping it was something that was set up wrong that I could fix. I do not have a smell problem unless I open it. It goes away quick just looking for options.

Ace · March 30, 2011, 01:03:15 PM

This topic has been discussed many times over and you will get just as many opinions. My combo tank is vented down and exits the bay floor then rearward wuth a baloney cut on the end of the pipe. I have yet to get any smell if ticket window is open or closed knorr has my bus blew up. At least that I'm aware of anyway. Nwck it may have and I'm not aware of it missing! Anyway, I guess the correct method if there is one is to vent it out the top but just to prove most theories aren't always correct, miner is as deceived and works just dandy. Ohhhhhhh by the way, I copied this installation from another bus nut and he too has no problems. His tank is square and mine is round if that helps.
Do it your way but sometimes when you go outside the box, you will find alternatives that work just fine and are simpler!

Lin · March 30, 2011, 01:12:18 PM

If you can access the tank, you may be able to see it there is what appear to be a vent pipe coming off it. If so follow it. Sometimes you will not see the vent on the roof because the builder ran it up under the refrigerator vent hood to avoid cutting another hole. That is the way mine is done. If there is no vent, I would look to the easiest way to create one. Fixing the the toilet will certainly make a big difference too.

eddiepotts · March 30, 2011, 04:37:42 PM

I looked and it has no vent. There is a bung off the top of the tank. It is a square tank. I will run a vent from it and see if it helps. there is already a hole in the floor so I will run it through there with a venturi first and see if it helps. I do see a small hole in the weld for the bung so I guess it has been venting a little. I hope this helps.

FloridaCliff · March 30, 2011, 04:42:01 PM

Eddie,

Lots of ways to skin this cat.

Mine is thru the roof, adding a venturi stopped a similar problem to yours.

Cliff

Chaz · March 30, 2011, 05:17:38 PM

I vented mine thru the floor with 2 pvc tubes. One is 2" and the other 1.5". The 2" has a 45* angle on the end right after it comes out of the floor and is angled back to "pull" (like a sand blaster). The 1.5" inch just goes out the bottom. The picture shows the 1.5" tube closest to you and the 2" on the other end of the tank.

It works fine and any sort of breeze will move the air thru the tank. I do not even get fumes in the coach when rollin down the road. That's nice!!!
As stated, it's definitely "thinking out of the box" and so far it seems to work quite well. But, as always, YMMD. I just wanted to come up with some way to not have to go thru the roof.
Chaz

p.s. Don't freak on the wiring. The pic was taken when I was working on that. It's cool. I promise.

eddiepotts · March 30, 2011, 05:29:22 PM

Chaz, I like that. Right above your valve I see a "t". Is that plugged?

Jriddle · March 30, 2011, 06:20:41 PM

I think you should get them out the top I have no trouble with smell. I have one vent for tank, one for the kitchen and one for the bath shower and sink. The pictures are of the tank and kitchen vents. The ticket window will suck you cup out if your are not watching.

John

Jriddle · March 30, 2011, 06:26:44 PM

Quote from: Chaz on March 30, 2011, 05:17:38 PM
I vented mine thru the floor with 2 pvc tubes. One is 2" and the other 1.5". The 2" has a 45* angle on the end right after it comes out of the floor and is angled back to "pull" (like a sand blaster). The 1.5" inch just goes out the bottom. The picture shows the 1.5" tube closest to you and the 2" on the other end of the tank.

It works fine and any sort of breeze will move the air thru the tank. I do not even get fumes in the coach when rollin down the road. That's nice!!!
As stated, it's definitely "thinking out of the box" and so far it seems to work quite well. But, as always, YMMD. I just wanted to come up with some way to not have to go thru the roof.
Chaz

p.s. Don't freak on the wiring. The pic was taken when I was working on that. It's cool. I promise.

Looks like with this set up there is a chance of sewage sloshing out of tank when it is near full.

My observation
John