Black tank access

subkron

When I use the black tank rinse I have water coming out bottom of trailer (even with pressure limited).  I have verified it is not the check valve or plumbing from the Nautilus box. Leads me to think it is the fitting on the tank.

When i had pulled the bathroom sink the black tank rinse plumbing from the check valve is accessible.

Does anyone know if the pex tube ( one on right in pic below) goes directly down to fitting? I'm wondering if I cut an access hole, circled in blue, whether I could see and tighten it up? Or maybe even a hole in front of pex lines.

MuttonChops

Here is a factory floor** picture of a 400 bathroom behind the sink layout.
Black Tank is in lower left.

** not sure nüCamp lets folks tour the build floor anymore

subkron

@MuttonChops Thanks for the view. I am trying to expand it to find the rinse connection but can't see it (using my phone). Do you have a pic with the rinse pex connected to the tank? Either way, I may attempt opening up an access to take a look.

MuttonChops

Only picture I have or have seen . . . . .
Just a Guess, the small white pipe near the shower basin is a good possible for the Flush Line

qhumberd

Here is the pic looking down on the two white lines that constitute the black tank flush and the one way check valve at the top







When I removed the sink on my 2019 400 I got some pics of the plumbing. A lot of folks were finding that the flush for the black tank was connected backwards.

I noted that the sink drainage and trap varied by model year, but the flush plumbing with the white hose lines on R is consistent



this is the valve. Maybe a connection is leaking if hooked up right.



Hope this helps

qhumberd

Found one more pic on outside wall when I pulled the outside shower. I recall that the white hose on L in the interior pic goes up to check valve and white hose on R goes down directly into top of black tank. My unit is pre Nautilus so this may not apply to you. Not sure how flush works in Nautilus systems.

Pic below shows supply from outside wall is hose nearest the black PVC. Far white hose terminates in top of black tank.

subkron

@qhumberd Thanks for the details.  I actually had an valve issue earlier this year where a stick bug crawled into the check valve and kept the valve from closing:
https://tab-rv.vanillacommunity.com/discussion/18140/stink-bug-in-black-tank-check-valve#latest

At that time, when I hooked up to the rinse inlet in the nautilus I was getting water into the shower/toilet area. Fixed that - and also placed a stainless mesh screen around it to prevent it from happening again. Now it leaks under the trailer but the check valve and interior (like the pic above) is dry.  

I was thinking that with the way they arranged the vent plus how the check valve is oriented that the rinse inlet to the tank is how you described, the rightmost line dropping directly to the rinse fitting.  

I think if I [carefully] cut a 4" hole (or use an oscillating tool to cut a rectangular access) between the sink drain and rightmost vent stack I may be able to, 1) see what is going on, and 2) maybe correct without removing the complete shower floor/toilet/etc.

I'm hoping the rinse connection to the pex is a threaded adapter that needs tightening.

Actually - while I'm typing this I will try a passive approach first.  I'll have to disconnect the pex that drops into the tank fitting at the check valve end. At that point I'll try to see if the pex can be rotated slightly and see if it appears that a fitting gets loose, hopefully at the rinse connection point. If so, I'll rotate the pex and see if I can get it to tighten enough without doing the whole cutting operation above.  If nothing happens they they may have crimped on the pex (which I doubt), the rinse fitting could be broken or the fitting to tank seal is compromised.

I will also ping nucamp and see if they let me know what rinse connection they are using, that may be a clue.

The camper is in use at this point so I may not be able to get back to this for a while.

qhumberd

@subkron hope its an easy fix. Not sure about the 2022 but it might be easy to get access by pulling the outdoor shower box. It s just 4 screws and some caulk and you can see the top of the black tank  where the rinse hoses attach in my model.

Good luck