I have never done that, but it certainly is possible with the Clean Dump system. When you shut off the on/off switch, the system stops pumping and if you close the valve at the end of the pipe going into the portable waste tank, no more waste will come out. If I were doing that, I would partially fill the portable tank from the black tank and shut off the valve to the black tank. Then open up the grey tank and pump waste out of that to clear the hose of black waste. When the portable tank is close to full, turn off the Clean Dump switch and close the grey tank valve. Then run the system for just a short time to clear the hose. It would work fine. I Dump "uphill" into my house waste line. The system will supposedly pump six feet up and 100 feet out.
__________________
|