Black tank flush leak

madtrout

We have had an intermittent problem with leaking around the drain when flushing the black tank. Has anyone else experienced this? It doesn't happen every time, so the dealer hasn't been able to duplicate the failure. I'm assuming it must be a problem with the check valve. Is there a way to access this area on a 2021 TAB400? Thanks, Mark

Bayliss

@madtrout, I'm not sure if this will help, but take a look at this discussion:

https://tab-rv.vanillacommunity.com/discussion/11608/leaking-black-water-tank#latest

madtrout

Hi Bayliss, Its not a leak in the drain tube itself, rather its leaking from around the drain where it comes through the bottom cover as if there is water building up under the belly of the trailer. 

Denny16

Does water come out the black tank drain after you turn on the tank wash?  If not, the check valve for the black tank wash is installed wrong way round, not allowing water into the tank.  There is a previous thread here about that issue.

The check valve is behind the sink unit in the head/washroom.  Here is a photo showing the valve:

The bottom red arrows point to the black tank wash connection for the check valve, which is behind the plywood support (top arrow)
cheers

madtrout

Hi Denny16, Yes the water does come out of the drain when I turn on the flush water. The flush definitely works. It is an intermittent problem, very puzzling. I'm guessing it is leaking where it attaches to the black tank itself, but not consistently. 

billspencer

I too had a leak at the fitting on the back of the Nautilus for the black tank flush. It had not been tightened at factory. Simple fix. In the process I had contacted NuCamp for pictures of the plumbing to the black tank and behind the shower panel. I'm posting these in case you want to know what goes where and the location of the vacuum check valve.

billspencer

Denny16

Thanks Bill for the photos, looks like a in-line connector (looks like a garden hose type connector?) coming from the Nautilus pipe to the hose going to the check valve.  This could be @madtrout ‘s problematic connection, which was leaking.  This is a bad spot for this type of connection, as there is no access once the outside wall is installed.  

Cheers 

Pintoplumber

If you’re talking about the black thing in the corner of the picture, that’s a vacuum breaker/backflow preventer. Eventually that’ll leak.

Denny16

No, I was referring to the small black connector at the bottom, circled in red (which is below the shower pan assembly):

The item in the green circle is the check valve, back flow preventer, and this can be accessed from inside the washroom, after removing the sink unit.  The check valve is well connected, and to date none have developed a leak.  The pre-Nautilus TaB00s have no connector between the outside Black Flush connector and the check valve connection that I have seen on similar construction photos.  This seems to be a new add on for the Nautilus assembly on the newer TaB400s.
 Cheers 

mjwaldner

I had a leek on the connector circled in red in the picture above. Very hard to get to to fix it.

https://tabforum.nucamprv.com/#/discussion/13283/2021-tab-400-bd-black-tank-flush-leak

Denny16

That was quite an adventure, but your tenacity paid off in finding a way in through the bottom of the closet/ 3-way fridge compartment.  Still not an easy task.
 Cheers 

madtrout

Hi All. An update to the leaking while flushing the black tank. I convinced nuCamp' s warranty and service departments to take a look at the problem even though my warranty was expired. I believe this was because I had reported the problem while still under warranty, but my dealer, Beckley's of Thurmont Maryland could not even replicate the problem, let alone fix it. It turns out that the black tank had to be replaced. The machine that spins on the water line connector to the black tank at the factory fast enough to melt/weld the connection had over-torqued the fitting and caused a break that allowed the leak to occur. It was a lot of work to replace it according to the tech. The entire bathroom had to come out and many pipes cut and replaced. When I got the trailer home there was a leak in the drain under the sink (not enough sealant at the connectors). I fixed it with a touch of JBWeld plastic putty. Long story, but I'm back in business. All the best, Mark

dragonsdofly

@madtrout thanks for the update. Often we don't hear how things worked out. 

Denny16

Glad glad you got it sorted, this is one leak with the most difficult solution and one for the books.
Cheers