Plumbing New Grey and Black Tank. Hope to get some help.

[Tony S]

Hi Folks,

I am moving along on the plumbing from the grey and new black tank. I have a couple of quick questions I hope you can answer to keep me out of trouble.

The work is being done on a 1973 Tradewind.

I have it rough in with the proper fall between 1/8 and 1/4”. I have heard it is best to use a no hub rubber fitting from the grey tank to take flex and movement into account.

Is this true? I put it about 4” off the grey tank outlet. Is this ok?

Finally, This is the most important question. I attached the Valterra 3" valve flange fitting to the black tank with about 2” of 3” abs pipe exposed past the outlet of the polyethylene black tank. I did this so I would have a chance to cut and repair it if necessary. I felt if I banged the fitting right up to tank outlet and adaptor I would be in a world of hurt if I had to repair or change it.

The problem is the now valve assembly goes past the original bumper position and I will have to extend the channel. It will give me a bigger box area that I would not mind.

Any advice on this? Should I jamb it up to the tank or leave space and extend the channel and position the bumper out a couple inches?

I’ll try and get a couple pictures to upload.


Many thanks. Any help would be appreciated.

Tony S

Rogue River, Oregon