Please help me understand proper venting and is there a typical toilet flange set bac

[Tony S]

Could some one give me a venting 101 lesson? I am ordering new tanks tomorrow, I hope. A black and a gray so I am lining things out so I can call out inlets.

When venting a sink is it proper to take vent off the drainpipe after the P trap? If I am see the old bathroom sink in 1973 Tradewind set up correctly, the 1½ Abs drain pipe goes into a 2” stack vent as the vent and water goes down to valve. This 2” stack also picks up the on deck black tank vent and below floor grey pipe (no tank) from kitchen sink and shower.

Related issue, I am planning on hooking the kitchen sink and shower to the new 25-gallon gray tank but wanted to pick up the low usage bathroom sink into the black. The new black tank is 25 gallon and the old was at the most 13 gallon. What I have heard is you typically run out of gray before black tank. Is this ok thinking?

Also is there a standard or typical set back from the wall for the toilet flange for RV toilets? I am concerned about placement fore/ aft on black tank.

Any help would be greatly appreciated.

Tony S

Rogue River

[Inland RV Center, In]

Originally Posted by Tony S

Could some one give me a venting 101 lesson? I am ordering new tanks tomorrow, I hope. A black and a gray so I am lining things out so I can call out inlets.

When venting a sink is it proper to take vent off the drainpipe after the P trap? If I am see the old bathroom sink in 1973 Tradewind set up correctly, the 1½ Abs drain pipe goes into a 2” stack vent as the vent and water goes down to valve. This 2” stack also picks up the on deck black tank vent and below floor grey pipe (no tank) from kitchen sink and shower.

Related issue, I am planning on hooking the kitchen sink and shower to the new 25-gallon gray tank but wanted to pick up the low usage bathroom sink into the black. The new black tank is 25 gallon and the old was at the most 13 gallon. What I have heard is you typically run out of gray before black tank. Is this ok thinking?

Also is there a standard or typical set back from the wall for the toilet flange for RV toilets? I am concerned about placement fore/ aft on black tank.

Any help would be greatly appreciated.

Tony S

Rogue River

I would suggest that you can the idea of running gray water, or even the possibilty of it, into the black tank.

Should for any reason, that black tank become over filled, the contents will line the gray water plumbing.

Then, you will have a problem that just won't go away.

Andy

[azflycaster]

The vents on the drain lines after the 'p' traps are to prevent the flow of water from siphoning the water out of the 'p' trap. Having the 'p' trap full prevents fumes from the sewer system from entering the trailer.

[Tony S]

Thanks Andy Advice take Idea canned. I remember reading your explanation about bacteria in the past now that you mention it.

Do you suggest separate vents for gray and black tanks?

Tony

[cameront120]

Originally Posted by Tony S

Do you suggest separate vents for gray and black tanks?

Tony

Absolutely! Each tank should be separately vented.

[cameront120]

Also, if you go to the Airstream site, they have owners manuals on line that show the plumbing for the waste water systems with clear illustrations. These are for new trailers, but the principle is exactly the same.

[TG Twinkie]

The black and grey tanks in my Argosy share a common vent stack. Original from A$. The point at which they connect is higher than the bath sink trap and the toilet.
I don't believe you could fill the black tank to the point it would flow into the grey thru the vent stack. Because the toilet bowl would not empty. That would be your first clue.
The same is true for the grey tank. When it gets full, it will back up into the shower/tub long before it would flow thru the vent system and go to the black tank.

[Tony S]

Below are pic of the vent arrangement I have taken out. You see the 2" floating I thought with the larger black tank I would just attach to it. But it appears it is a bad idea. The 2" is what went directly to valve past tank.

The third picture is of the galley sink/vent. If this run attaches into the gray tank will that satisfy the need of venting the gray tank?

Thanks

Tony

[TG Twinkie]

Are you saying the 2" floating went to the pipe where the dump valve is attached or to the old black water tank?
What I see is pretty close to what is in the Argosy I have as far as the tanks go.
Is the tank in the pics the grey water tank? If it is, I'm assuming you want to connect the "floating" pipe to the black tank. Is this correct?

[Tony S]

Yes, the 2" pipe met up with the shower drain pipe on the curb side of the valve after crossing underneath the trailer. On the street side the shower came in. I believe that is how it was.

[TG Twinkie]

I don't recall you saying what year the trailer is. Did it have a grey tank? Judging by the last pic you posted, I would guess NO!. Because of the plumbing cross below the black tank dump valve.
Are you planning to use the 2" pipe to drain the grey tank into the plumbing cross?
I think you meant to say the shower came in on one side and the sink on the other side of the cross. Is that correct?

[Tony S]

It's a 73 Tradewind. No, I will drain into new grey tank with either 1 1/2 or 2". Whatever I find out is recommended. I keep going back to a couple of super threads one by Lance McEwan who I will flatter as much as I can, that is to say copy what he has done. I am ordering the same tanks. Only one grey and one black.

http://www.airforums.com/forums/f36/...h-73643-5.html

Al