Plumbing Issue, Little Help Please

[ArmyEOD]

My son just purchased a used TT. it is a 1997 Sunline 2970 model, It spent most of it life parked in a garage and is in great shape. However it does seem to have one issue. The other night when he brough it to a local campground to flush the tanks he noticed that once the black tank was empty, he thinks that water was still comming in. He said there was no water collecting in the bowl, but when he looked down the "hole" he thanks that the level kept coming up in the tank. He also said that the level indicator showed that the water level was rising. He said he could not see any dripping water from inside the bowl or any reason for it to keep filling other than the fact that he was hooked up to city water.

He has all the manuals and I have read them on the plumbing section/drawings and can see no reason for this water. The fresh water line goes to the flush valve. The black tank has the main drain on bottom and a seperate vent that runs to the roof. It is a 30 gallon black tank.

I will check tonight to ensure that no water is seaping past the flush valve, but if it was it should collect in the john.

I will double check to be sure a flush out nozzle has been installed and a valve is open/leaking somewhere. Any other ideas.

[Tha_Rooster]

I would think the flush valve is leaking or someone flushed to collect in the black tank.

[paz]

Is there a black tank rinse? If there is, it should be a separate hose connection, but the previous owner could have somehow plumbed it into the trailer water system. If he did and the rinse valve was left on, that could account for the rise in level inside the tank.

[Ramblin]

If there is one thing to learn from this forum, it is to NEVER assume a used RV has not been modified by the previous owner. In fact, if THESE RVers are any indication, it would be safe to assume the opposite to be true.

Really, there should be nothing going intothe black tank that doesn't go down the toilet. One exception is the tank flush port. My coach has a dedicated port, not connected to the fresh water system, that I have to connect a hose to. Its right next to the city water inlet, so make sure your city water is connected to the right inlet. Previous owner may have plumbed that black tank flush port to the fresh water system, check that.

The previous owner may have installed a tank balance mechanism to move grey water to the black tank. Some folks do this to maximize holding capacity and thereby lengthen the time between dumps. Most often I hear of them using a separate pump for that, but I suppose it could be a gravity system if the tanks are positioned to allow it.

You might be able to turn off the water at the toilet to eliminate it as the source.

[1ciderdog]

May not apply in your case but I remember reading on some units the bathroom sink may drain into the black tank - to add more fluid to the black tank for obvious reasons.
Safe Travels
Bob

[ArmyEOD]

Up-Date, thanks for the replys. I have gone over the entire plumbing system. The way it was built nothing is hidden from view (every pipe is visable through a cabinet, closet or access panal.) I can trace visualy every inch of the plumbing from the water inlet to the the HW tank to the shower, bathroom sink and the kitchen sink (end of runs). There is no cross over pipe between tanks either. It has two vent pipes but no cross over there either. I am going to remove and inspect/repair or replace the flush control valve, I am 99% sure that is the demon. It is a very slow flow where every it is. Wish me luck and I will re-post later today.

Happy Trails

[EMD_Driver]

Did you ever find the culprit?