Waste valve

[Apache_Camp]

What do I need to do to install a new 3" size waste valve to the end of my main drain?

[azflycaster]

From previous post I think I know what you are trying to do. The valves for your black and grey tanks are not functioning and your plan is to place a valve at the exit point of your trailer to hold everything back and then dump everything at once. I can see a problem with this setup.

I believe that your tank arrangement is the same as my 75 Trade Wind. The black tank sits above the floor and the grey tank is below the floor. With one valve at the end of the exit pipe, everything will first enter the grey tank. When that fills, it will then start to fill both the black tank and the shower floor at the same time since they are at the same level.

Contaminating your grey tank is not a good idea and filling your shower with a mix of black and grey water is just wrong.

[Apache_Camp]

Yeah, that was the idea. Right now neither valve is working...I put a the cap on the end of the tank and ran clean water in both tanks and could not get either to "backup". Can I get a replacement for the stock valves, they seem to be 3 1/2" or so and the replacement valves I've found are 3". I'd really like to just convert the whole thing to standard 3" setup instead of having to use adapter and this and that on the trailer.

(Also, can you send me instructions on how you mounted your new converter? I think we bought the same converter and theres no place to hook up anything on the new converter. I guess I could buy some type of fuse block and add it on)

[Argonaut20]

Are you talking ID or OD on the valves? Valves are normally 3 inch ID (interior diameter) and will measure about 3 1/2 inches OD (outer diameter). I may be off the wall, but I have never heard of waste valves on an AS or Argosy that were 3.5 ID. You should be able to use the standard Thetford 3 inch waste valve with 3 inch pipe to replumb the system. azflycaster is right: you will get brown floaties in the shower if you cap the end.

[DaveFL]

There are good reasons to have an end cap valve, when the grey is full and the black shows empty or 1/3, it is possible to use the end cap valve to allow some of the grey to back syphon to the black.
When I had two valves go bad I was able to use the end valve as an emergency stop so that you can put off the job of replacements if you monitor and keep tanks almost empty.

[kennethowens]

Pull the two old valves ... replace them or rebuild them

[Apache_Camp]

I looked at it yesterday, after I removed the aluminum shroud in the bumper compartment, I could get to the valves easier. They are both white and look like replacements. With a little wiggling I got the black tank valve to work, the grey tank valve is stuck shut...I'll replace it eventually.
I ordered a new 3" Twist On waste gate valve, I'm going to remove the old end and mount it on the end of the waste pipe in place of the original AS twist end, that way I'll have the correct size end for the sewer hose and a valve at the end as well.

RV Camper Twist on Waste Valve, 3":eBay Motors (item 190326894150 end time Oct-05-09 13:23:42 PDT)

[Apache_Camp]

I cut off the old waste valve end. I added a 3" curved pipe and a new waste valve with the new style connection.

This setup allows me to still open/close the gray/black valves but now I don't have to use the adapter for modern sewer line. (It seems to work ok in the back yard.)

The hardest part was cleaning and sanding all the years of paint off the black pipe from the trailer, so that I could glue the connection on.

[Aage]

Originally Posted by DaveFL

There are good reasons to have an end cap valve, when the grey is full and the black shows empty or 1/3, it is possible to use the end cap valve to allow some of the grey to back syphon to the black.
When I had two valves go bad I was able to use the end valve as an emergency stop so that you can put off the job of replacements if you monitor and keep tanks almost empty.

Do you think this would work when the black tank is above the floor and the gray is below? I don't.

Here's the photo that Apache_Camp posted, lightened a bit.

[DaveFL]

Originally Posted by Aage

Do you think this would work when the black tank is above the floor and the gray is below? I don't.

Not likely.
My black tank is above and below while the grey is only below and very shallow, that is why it would work for a small amount of grey if black is almost empty.

[Apache_Camp]

The waste valve is on the end of the drain pipe, it does not affect either of the tank operations under any circumstance. Both tanks still have their original drain valves.

The only thing it does is keep waste water off of you when you hook up. It does allow you to hook up to the new style waste drain pipe without an adapter.