2003 Roadtrek holding tanks delimma

[GadFly]

Wow.. Really puzzled...Are there an upper and a lower black water tank?
My black water is not draining..
Fluids are at the bottom of the potty level.
Opened dump valve and got a very minor fluid trickle. no solids..
Suspected dump valve cable/shaft had separated from the slide gate.
Dropped the extension tube/drain hose assembly and back flushed with garden hose.. Was able to push about 10 foot of garden hose in..... Apparently gate valve and line is clear all the way into the tank...
Went up topside and probed downward into toilet.. Expected there to be a blockage in the adapter into the holding tank from the toilet base..
Not so , it seems. Does not appear to be an adapter pipe-drop into the tank, appears to be another tank, the space below the potti appears to only be about 8" deep; yet it is much farther distance to the elevation where the tank bottom should be..and that space appears to be a tank also. Is it possible to have a blockage in the connection between, what appears to be, two tanks?
(grey water drains fine).

[jrobe]

I have seen some pictures of unusual, custom shaped Roadtrek tanks. Here is an example. I would do a search for your particular model and see if anyone is selling a replacement to get an idea how it is shaped and configured.

https://www.mobiliferv.ca/rv-parts/r...ack-tank/6276/

[GadFly]

Originally Posted by jrobe

I have seen some pictures of unusual, custom shaped Roadtrek tanks. Here is an example. I would do a search for your particular model and see if anyone is selling a replacement to get an idea how it is shaped and configured.

https://www.mobiliferv.ca/rv-parts/r...ack-tank/6276/

I think you nailed it!
First chamber above the Van floor; 2nd chamber below the floor.

Great
Thanks

[lel]

I had the same problem last year. I had forgotten that there is a second drain valve behind the left entry door to the coach That drains the toilet from the upper black tank on our 2003 RT. Open that door and it is down low by the fire extinguisher.

[rowiebowie]

That is a really bad design. But once again, our knowledgable members are here to help!