2024 Grand Design Transcend 235BH Bathroom sink plumbed to black water tank

[Cflaxy]

Hello everyone. We just purchased a 2024 Grand Design Transcend Xplor 235BH about a month ago. On our last trip out, we noticed that our black water tank was filling up very quickly and so we decided to run each of the sinks, shower and toilet to see what was going where. As we speculated, the bathroom sink is plumbed to the black water tank. That sink has the most pressure of any of the faucets in the trailer. Therefore, releasing a significant amount of water every time you wash your hands or brush your teeth. Water tank filled up in a day and a half. If you’re boondocking that is not a good thing. Anyone else have experience with this? Thank you.

 

[Riverbug]

You're saying that when you put water in the sink, it goes into the toilet tank? That would have to be quite an error by the manufacturer, but I suppose not inconceivable. If it isn't something you want to dig into yourself, I would definitely take it to the dealership and have it corrected. The only water going into the black tank, should be from the toilet.

 

[Cflaxy]

That is correct. I took it to the dealer and they said they called grand design. Allegedly, grand design told them that this model is plumbed this way. That makes absolutely no sense whatsoever. I have NEVER heard of ANYTHING being plumbed to black other than the toilet. I have a call into grand design myself and I will see what they say.

 

[Hoopy Frood]

It's not completely unheard of. Our Momentum has the rear bathroom sink plumbed into the rear black tank. But does seem odd that the black tank seems to be the main drain for the bathroom.

 

[Riverbug]

That is correct. I took it to the dealer and they said they called grand design. Allegedly, grand design told them that this model is plumbed this way. That makes absolutely no sense whatsoever. I have NEVER heard of ANYTHING being plumbed to black other than the toilet. I have a call into grand design myself and I will see what they say.

I actually have never heard of that before. Seem pretty ridiculous to me, but as @happyfrood stated I guess that would make sense with second half bath situation. I would be pulling the Coraplast to see what I could do to correct that although, what a PIA! That would be very frustrating to me to find out after purchase.

Edited to correct spelling of Coraplast. I noticed somehow it changed it to Craplast, which probably isn't entirely off base.

 

[Cflaxy]

We only have one bathroom and the shower is plumbed to the grey so I don’t know why the sink isn’t. The black is only 39 gallons so with brushing teeth for 6 people and hand washing ever time you use the bathroom it fills up fast. Ugh…